Hard to say for sure, when I was in school I felt like I was banking on technology becoming cooler over time which does seem to be the case.

There's also less pressure on men to settle down early. A man can more easily think "fuck it, I won't start dating until I'm 25 by which time I'll be successful, drive a nice car and be an eligible bachelor".

With the whole biological clock issue women are often hoping to be married and starting a family by that age or risk being seen as the archetypal "cat lady".