Having 'drinks with friends' is not morally wrong, in and of itself; it often is, in today's day and age, but we don't know the full circumstances. I've gone out to 'have a drink' with friends from Church more than a few times. I don't know that I would approve of my wife or sister doing so. Having drinks when you have a 2 week old baby may be morally wrong, and is, at a minimum, bad parenting from a Traditional Catholic perspective; but it not unheard of in our society. There's the idea that having a baby is somehow so taxing on new mothers, that they now need before and after pregnancy massages and getaways; its so unnatural for modern man and woman to go through having children.
Its an extraordinary event- to have a child- to those who live and die by our world. Of course the banksters have been successful at convincing by marketing that there are new 'minimums' that we need to have babies; not only in the way of material things, but those things like I'd mentioned above that are somehow supposed to 'recharge' you after having a child. The, "I'm focusing on me now" is nothing new or surprising to us.
At the end of the day, PW said yes. If her conscience has her questioning her decision, she should go to her father confessor for advice. I see nothing wrong with her decision given the circumstances; would I advise her to do it in the future? No. But she should be proud that she is realizing these things and questioning them. This is part of spiritual development. Things she's done before, she will not do anymore. She will make mistakes, and this is why her father confessor should be the one she confides all to in the confessional.
One can not negate the fact that there is a transition we all go through in our lives- whether we're born into Tradition, or find it later in life- its called conversion. Its a process that never ends. As long as we strive to reach our Blessed Lord with humility, and practice the virtues of Faith, Hope and Charity, his promise will reign true for us individually: "behold I am with you all days." Of course the best way to Him, as he wants it, is through his Blessed Mother, the Mediatrix of all Graces. Turning to her to reach her son is what he wishes.
We can remember the words of St. Louis De Montfort, especially since there is someone who has taken his namesake here, to help us understand this:
"It was through the Blessed Virgin Mary that Jesus came into the world, and it is also through her that he must reign in the world." "God has decided to begin and accomplish his greatest works through the Blessed Virgin ever since he created her, we can safely believe that he will not change his plan in the time to come, for he is God and therefore does not change in his thoughts or his way of acting." ". If devotion to the Blessed Virgin is necessary for all men simply to work out their salvation, it is even more necessary for those who are called to a special perfection. I do not believe that anyone can acquire intimate union with our Lord and perfect fidelity to the Holy Spirit without a very close union with the most Blessed Virgin and an absolute dependence on her support."