Megan McArdle, at The Daily Beast:
But as a general rule, you should err on the side of marrying early. By which I mean not that you should marry whoever happens to be around when you turn 22, but that you should be willing to recognize, at the age of 22, that you've found someone you want to marry. Right now, most Princeton students don't think that way. They think there's something weird about committing at 22. And if they try to commit, their friends and parents will warn them off.
I got married at age 22 and it changed my life forever, for the better. As a bonus, we'll have all four of our kids by the time I'm 30 and I'll be able to raise them while I'm still young and relatively energetic. I think getting married at a young age is a wonderful idea.