It completely depends on the individual.

However, women tend to "marry up", so you'd have to be her superior in one or more ways for such a marriage to "work". She needs to be able to look up to you in one (preferably more than one) department. You wouldn't want to feel like she was your superior, assuming you're planning on being the man (that is, the head) of the relationship.

That goes for maturity, being established, earning power, knowledge of the Faith, and other topics.

Im a 19 year old Traditional Catholic guy. Very mature for my age ( melancholic scholarly type) I'm thought about the priesthood, but a part of me does think God is calling me to marriage. One big problem is that the vast majority of Catholic women I know are either Feminists or NeoCons. There are very, very few seriously   Traditional women out there, so a guy can't be too picky. There are some girls I'm interested in who are a couple years older than I. What's a reasonable age gap?

Everything Nadir said kind of "goes without saying" when it comes to finding a relationship -- the topic is much broader than just age. But since that was the specific topic of your question, I was strictly addressing the age issue.

But I forgot to mention something else -- "a part of me does think God is calling me to marriage". Hopefully it's not a part that resides below the waist. I know that's a bit blunt if not crude, but I'm serious. My point is: don't think that priests, or men called to the priesthood, are fαɢɢօts, asɛҳuąƖ (as in: not interested in sex, or no sex drive), defective in testosterone, and/or not attracted to women. Because that is not true! As at least one individual pointed out, if you aren't attracted to women that might be an impediment to the priesthood, and the seminary shouldn't want you, because perhaps there's something wrong with you (such as the emotional/mental/spiritual disorder of ɧoɱosɛҳųαƖity).

A priest is a man like any other man -- except he makes a noble sacrifice of having a family, and unites his whole life with the sacrificial life of Christ, up to and including His Passion and Death.

A priest is not a misogynist. He doesn't hate women, he just loves God more and wants to serve Him in a special way to help bring souls to heaven. 

It's not that a priest isn't attracted to women -- it's that he has built up virtue (both natural and supernatural) and lives a life of self-denial and mortification -- perfect chastity is only one of the ways this is manifest. There are many other virtues as well that he will practice.

Long story short, every man considers marriage or is attracted to the idea of marriage to some degree, because A) it's natural, B) the institution of Marriage is good and created by God, and C) it's the "default path", or the way of all flesh, as it were. The only way you should reject marriage is for something higher, such as to give yourself to the religious life, the priesthood, or even a special apostolate/calling as a single person (single people have more time than anyone else, and a huge temptation and ability to be completely selfish. So watch out on the "single" vocation...)

But that is why you try out a vocation to the religious life/priesthood FIRST, before you get married, and see if God wants you. Then, if He doesn't, you can go in peace and go find a wife. But even then, if you don't manage to find someone suitable even after a long period of time, it could be that God is not calling you to marriage. Don't settle or be desperate. God won't call you to marry a non-Catholic, for example.

I think for Marriage, 10 - 15 years or so difference is ideal, the man being older, considering the biological differences between the sexes. I have met couples where the man is even 20 years older and they work fine.

I think for women the ideal age for Marriage is 18 - 22 years old.

I was asking more about ideal  difference in the case of women being older.

I think that ideally women should not be older.

Women and men age very differently.

Women prime years 22 years of age

Men prime years 35 years of age.

As I said, 10 - 15 years of difference is good, in ideal circuмstances.

That math isn't looking good for him. : )
Seriously, though, OP, you said you just started college. Unless you're already planning to quit and pursue a different employment path, I think you shouldn't worry about marriage until you're further along.

Just finished freshman year. All of this stuff ( marriage/priesthood etc) is just a thought right now. BTW, I go to a tiny Catholic college that is saturated with Novus Ordo  Neoconservatism. Someone  here probably knows which school I'm talking about.

True. He is only 19 .

I think he is better off building some wealth these years and working on how to eventually be able to support a wife and children. Focusing on a trade or a career at this age would be very good for him. Then at 28, he could marry a 18 year old girl and be able to offer her a decent living .

The issue is that even at 19, most 18 year old girls are far too immature for my liking😀

Coming from a very large family and having a large family myself, i can give you what seemed to work for us...

If you have an inkling to the priesthood but don't like dealing with people's problems, maybe God is calling you to be a monk.  Every young man should at least try out religious life for two years before considering marriage. 

Marriage should not be in your vocabulary until you are old enough and have direction in your life to be able to support a family.  

A man should never marry an older woman.  He will not be looked up to.  And I disagree completely on a huge age gap, too.  Not more than 5 years.  Can you imagine a 30 year old man looking at a 15 year old for marriage?  Sends shivers down my spine just thinking about it.  Bleh...

It IS difficult for men and women both these days to find a suitable spouse.  But, if He wants you married, He will send you a spouse.

My suggestion to you is to pray for the grace of many strong virtues to be able to discern His holy will for you.