One aspect: I feel once you start thinking about having a family (and not being a farting old decrepid mess by the time your children are 20yo) you really start looking for someone who can be committed and would be interested in starting one, and that really doesn't include hot 20yo girls.

Another: People who age gracefully show they can take care of themselves and look amazing any age. That is powerful. Combined with the fact 25+ have a much better sense of style and manners, and understand the world so much more in a nuanced way.