I was 21 and DH was 22 when we got married. We'll be married 27 years in a few weeks.
On the other hand, my brother married a girl that was 20yo. She was married and divorced with 2 children by the time she was 15yo. Needless to say, their marriage didn't last too long either.
Yikes! Can 15 year olds even legally get married?
Apparently in Arkansas they could. She was married at 14 and divorced by 15. When my brother moved there, he said that everyone assumed he was gay because he wasn't married yet. He was 19yo! Much different from the suburbs where he grew up.