People have different capabilities for recollection. You just may not have such an aptitude, that's all. Nothing I would worry about, it can be a blessing and a curse.
I personally have an extremely good memory, but it can also torment me given that I was not Catholic until I was 27, therefore, I can recollect many of the horrible sins I've committed in my past life vividly. Which Satan certainly uses to tempt me in thought very often. But also blesses me with an example of how not to act in my new life of grace.

As for the Catholic understanding of memory, there's a whole section in the Catholic Encyclopedia on the subject, with distinctions between intellectual and sensible memory
https://www.newadvent.org/cathen/10174a.htm

St. Thomas Aquinas and Augustine both extensively examined the idea of memory, with Augustine tending toward a more Platonic form of reminiscence.

This is interesting.  In my experience, men remember a lot more from their past than women.    

People have different capabilities for recollection. You just may not have such an aptitude, that's all. Nothing I would worry about, it can be a blessing and a curse.
I personally have an extremely good memory, but it can also torment me given that I was not Catholic until I was 27, therefore, I can recollect many of the horrible sins I've committed in my past life vividly. Which Satan certainly uses to tempt me in thought very often. But also blesses me with an example of how not to act in my new life of grace.

As for the Catholic understanding of memory, there's a whole section in the Catholic Encyclopedia on the subject, with distinctions between intellectual and sensible memory
https://www.newadvent.org/cathen/10174a.htm

St. Thomas Aquinas and Augustine both extensively examined the idea of memory, with Augustine tending toward a more Platonic form of reminiscence.

Something I think about constantly is that memory may not lie in the brain. There's stories of people with heart transplants and other organs that begin to remember things other people did. This tends towards a disembodied soul because what of the nature of those organs would give rise to memory? Egyptian pagans seemed to think memories lied in the heart.

Likewise I have been graced with a great memory, which was very painful when I converted and continues to be a source of pain. My general took me about a month to put together and I'm still working on tracking various people down I need to make reparation to etc. I really have had to put a "lock" on my memory in certain periods of my life and just try my hardest to forget, of course I can't but it's the best I can do: not ever do things or think things that will "take me back" to that point in any sense. I suppose this has created some weird mental boundaries but they absolutely have to be there as safeguards.

Only if having a good memory was still an employable skill!

 I would imagine part of the reason your 21 year old son has clearer memories of his childhood is the fact that there are more pictures and videos of it than there are of yours. I think about this with my own kids, who have (from a young age) been exposed to many more images and videos of themselves than I was. 

So if God forgives and forgets does that mean that when we are judged we are only judged on the sins we die with?  Was St. Jean Vianney wrong when he wanted to go off and weep over his sins?
So if we confess,receive Communion and Extreme Unction right before we die there will be nothing that God remembers on which to judge us.
Great !  I thought everything was written down.

Absolutely, God completely forgets our sins.  Perfect forgiveness entails never having it come to mind ever again.  If someone grieviously offended me, and I "forgive," due to my imperfection, every time I see that person, I still think of what the person did even if I don't "hold a grudge".  But God's forgiveness is so perfect that when He sees you, He retains no memory of the wrongdoing.  These sins might as well have been committed by someone else, and in fact they were, since after Confession Our Lord "makes all things new".

When we are judged at death, we are in fact only judged for the sins and the effects of sin that still remain in our souls, and any debts that remain as a result of our sins.  But the sin as sin no longer exists.  There was a time that there was a historical event where we did something, but that thing is no longer reckoned by God as sin, but just as a thing that happened.

I don't believe for one second that during our judgment, God will accuse us of already-forgiven sins.  We will be evaluated based on the current state of our souls, and the review of our lives will entail seeing the mercy and grace of God, how they were present with us throughout everything.

Our sins have effects and they have an impact.

Take this example.  I sneak up in the dark with a mask on and punch someone in the face and break their nose.  That person doesn't know who I am.  But the next day I go visit him and see his broken nose.  So I am heart-broken by the sight of it, and I grieve at the pain being experienced by the person, and yet the person holds absolutely no grudge against me (not knowing that I did it).  Perhaps he even shakes my hand, gives me a hug, and thanks me for coming to visit him.  So you can still grieve for the effects of your sins, even if the other person holds zero grudge.  So God, after He forgives our sins, has the same disposition toward us as this person who holds absolutely no grudge, because He does completely forget the sin.  Similarly, we caused Our Lord incredible suffering due to our past sins, and we grieve for His suffering rather than, in a self-centered way, grieve over the harm that we had caused to ourselves.  So when a St John Vianney wept for his sins, it was with no thougtht to himself whatsoever, but 100% focused on the suffering of Our Lord.  Most of us, when we grieve for our sins, may have some sadness over the suffering we caused God, but a lot of it is rooted in self-pity, focusing on the harm we did to our own souls, and the blow that is to our own egos.

Another analogy is that I accidentally smash into somenone's parked car.  It was a total accident.  So the person holds no grudge whatsoever.  That doesn't mean I didn't wreck his car.  So I owe him the cost of fixing it up.  Now, compare that with if I deliberately damaged the car.  That person then holds a grudge.  PLUS I owe him damages.  So, when God forgives a sin, He places the sin in the first category, where it's accidental damage and no longer remembers the sin part of it, that it was deliberate and malicious.

So when we die, we may owe, in spiritual currency, thousands of dollars of damages, but if the sins have been forgiven in Confession, there's no recollection of any malice involved ... it's just a straight out objective debt.

THAT is how perfect God's forgiveness is.  And the sin AS sin ceases to have any existence and no longer exists in His mind.  If something isn't in God's mind, it has no existence whatsoever.  Sin as historical event was known to have happened (just like with the car analogy, where in both cases the car was objectively damaged), but it's now in the same category as if had been accidental and without malice.

We also must be purged of the imperfections and selfishness with which we die.

If we only knew how perfectly God forgives and forgets, we would be overflowing with love and gratitude, for that complete and perfect forgiveness and re-creation which He purchased for us at such great cost.  Our Lord's Passsion absolutely destroyed all sin for those who received His forgiveness in the Sacraments.

When we see someone, in our worthlessness, we might think, "oh, yeah, there's the guy who was a fornicator" or "that guy was a sodomite".  No such recollection occurs in God with us for the sins He has forgiven.

God wished to free us entirely from the chains of sin, and we don't give enough credit to the power of His Passion and the perfection of His forgiveness ... since we are incapable of truly grasping it, until the next life.

I think that people have an entirely mistaken view of how God will judge.  We have this false conception that He will rub our noses in our past sins.  See what you did there!  How about this!  That is to sell God infinitely short.  That's not forgiveness, is it?  If I say that I forgave an adulterous spouse, but then every time I get into an argument, I bring it back up, "you adulterous whore!" ... is that actually forgiveness?  Not at all.  God is not like that.  His forgiveness is perfect and the sin, as sin, will never be brought up or mentioned by Him again or thought of by Him again.

We will be judged for our current state of soul and also need to make recompense for the damage we caused (as per the accidental vehicle damage), but God will not hold our forgiven sins against us.  But even these debts Our Lord will forgive to each of us to the extent that we forgive others.  If we hold our neighbors debts against them, then God will sent us over to the torturers until He has extracted every penny that we owe.  Notice, not forever, since the guilt of sin has been forgiven, but just until the debt itself has been paid.  And the debts of our sins are in the billions of dollars.  If we won't forgive the 50-cent debt owed to us by others, then God will extract every penny from us.  But if we forgive our neighbors all their debts, then God will forgive us up to the entire amount owed.

Exorcists have reported that the demons have no knowledge of any sins committed by those performing the exorcism if they have been forgiven in Confession.

That's interesting, as I thought +Ripperger said the opposite, specifically referencing porn, of which the demons can pull images to tempt.

Absolutely, God completely forgets our sins.  Perfect forgiveness entails never having it come to mind ever again.  If someone grieviously offended me, and I "forgive," due to my imperfection, every time I see that person, I still think of what the person did even if I don't "hold a grudge".  But God's forgiveness is so perfect that when He sees you, He retains no memory of the wrongdoing.  These sins might as well have been committed by someone else, and in fact they were, since after Confession Our Lord "makes all things new".

When we are judged at death, we are in fact only judged for the sins and the effects of sin that still remain in our souls, and any debts that remain as a result of our sins.  But the sin as sin no longer exists.  There was a time that there was a historical event where we did something, but that thing is no longer reckoned by God as sin, but just as a thing that happened.

I don't believe for one second that during our judgment, God will accuse us of already-forgiven sins.  We will be evaluated based on the current state of our souls, and the review of our lives will entail seeing the mercy and grace of God, how they were present with us throughout everything.

Our sins have effects and they have an impact.

Take this example.  I sneak up in the dark with a mask on and punch someone in the face and break their nose.  That person doesn't know who I am.  But the next day I go visit him and see his broken nose.  So I am heart-broken by the sight of it, and I grieve at the pain being experienced by the person, and yet the person holds absolutely no grudge against me (not knowing that I did it).  Perhaps he even shakes my hand, gives me a hug, and thanks me for coming to visit him.  So you can still grieve for the effects of your sins, even if the other person holds zero grudge.  So God, after He forgives our sins, has the same disposition toward us as this person who holds absolutely no grudge, because He does completely forget the sin.  Similarly, we caused Our Lord incredible suffering due to our past sins, and we grieve for His suffering rather than, in a self-centered way, grieve over the harm that we had caused to ourselves.  So when a St John Vianney wept for his sins, it was with no thougtht to himself whatsoever, but 100% focused on the suffering of Our Lord.  Most of us, when we grieve for our sins, may have some sadness over the suffering we caused God, but a lot of it is rooted in self-pity, focusing on the harm we did to our own souls, and the blow that is to our own egos.

Another analogy is that I accidentally smash into somenone's parked car.  It was a total accident.  So the person holds no grudge whatsoever.  That doesn't mean I didn't wreck his car.  So I owe him the cost of fixing it up.  Now, compare that with if I deliberately damaged the car.  That person then holds a grudge.  PLUS I owe him damages.  So, when God forgives a sin, He places the sin in the first category, where it's accidental damage and no longer remembers the sin part of it, that it was deliberate and malicious.

So when we die, we may owe, in spiritual currency, thousands of dollars of damages, but if the sins have been forgiven in Confession, there's no recollection of any malice involved ... it's just a straight out objective debt.

THAT is how perfect God's forgiveness is.  And the sin AS sin ceases to have any existence and no longer exists in His mind.  If something isn't in God's mind, it has no existence whatsoever.  Sin as historical event was known to have happened (just like with the car analogy, where in both cases the car was objectively damaged), but it's now in the same category as if had been accidental and without malice.

We also must be purged of the imperfections and selfishness with which we die.

If we only knew how perfectly God forgives and forgets, we would be overflowing with love and gratitude, for that complete and perfect forgiveness and re-creation which He purchased for us at such great cost.  Our Lord's Passsion absolutely destroyed all sin for those who received His forgiveness in the Sacraments.

When we see someone, in our worthlessness, we might think, "oh, yeah, there's the guy who was a fornicator" or "that guy was a sodomite".  No such recollection occurs in God with us for the sins He has forgiven.

God wished to free us entirely from the chains of sin, and we don't give enough credit to the power of His Passion and the perfection of His forgiveness ... since we are incapable of truly grasping it, until the next life.

I think that people have an entirely mistaken view of how God will judge.  We have this false conception that He will rub our noses in our past sins.  See what you did there!  How about this!  That is to sell God infinitely short.  That's not forgiveness, is it?  If I say that I forgave an adulterous spouse, but then every time I get into an argument, I bring it back up, "you adulterous whore!" ... is that actually forgiveness?  Not at all.  God is not like that.  His forgiveness is perfect and the sin, as sin, will never be brought up or mentioned by Him again or thought of by Him again.

We will be judged for our current state of soul and also need to make recompense for the damage we caused (as per the accidental vehicle damage), but God will not hold our forgiven sins against us.  But even these debts Our Lord will forgive to each of us to the extent that we forgive others.  If we hold our neighbors debts against them, then God will sent us over to the torturers until He has extracted every penny that we owe.  Notice, not forever, since the guilt of sin has been forgiven, but just until the debt itself has been paid.  And the debts of our sins are in the billions of dollars.  If we won't forgive the 50-cent debt owed to us by others, then God will extract every penny from us.  But if we forgive our neighbors all their debts, then God will forgive us up to the entire amount owed.

Thanks for this!

And what about plenary indulgence for the debt owed?