In most western countries, middle-class men typically do not marry until they are able to support a family, whereas women married when they were able to start raising a family, leading to a substantial age gap, since men traditionally had to complete things such as apprenticeships, college, building a career, fighting wars – before they go married.
Of course, disreputable teenagers always were, well, you know (we can’t discuss it here) -and they were disreputable with people their own age.
Increasing, women have been delaying marriage in order to enter careers, leading to many women being upset once they hear their “biological clock ticking.”
In all fairness, women seem to be emotionally ready for parenting a lot soon than men.
I suspect the norm in the frum community will gradually be for men to marry in their late 20s or early 30s, and women to marry in their mid 20s. Remember that unless they are “1%” types, women as well as men need time to finish college and have a career so they can support a family in a middle class manner (including paying tuition).