I wrote about adulthood a couple days ago, and here's an article that gives the results of a survey in which people were asked what ages are appropriate for various life events.
Financially independent: 20.9I'm not sure how you're supposed to be living with your parents and financially independent at the same time, but whatever. The results don't take into account the fact that the median age for women's first marriage is 25 and the median age for men's first marriage is 27, but then it's just asking for peoples' opinions.
Not living with parents: 21.2
Full-time employment: 21.2
Finishing school: 22.3
Able to support a family: 24.5
Marriage: 25.7
Have children: 26.2
This Washington Times article describes how the attitude of young men towards marriage has changed over the past couple of decades and explores some of the reasons. The author, Cheryl Wetzstein, argues that "commitment phobic" men are are bad news for young women who are looking to build a family before their fertility starts to decline (at age 27, ladies), and she attributes much of this change in attitude to the decline of traditional social forces that used to push men towards marriage more strongly than they do now.
I think our generation is reaping what was sown during the "sexual revolution".