I'm 38 and still not married even though I've been with my SO since age 20. There are a lots of reasons we haven't married. We are not religious, family problems, he was in college until age 25 then it took him a long time to get a permanent job. I sometimes wonder how things might have been different if I'd married my previous bf. I'd probably have grown-up kids by now, like some of my friends.
I don't think age matters as long as you're sure you're marrying the right person. Age doesn't always bring wisdom and certainly doesn't give you the ability to predict the future. My friend got married at 20 and had 4 kids right away, one after the other. She is very happy and is now looking to get herself a career.