I got married in 1997. I was 22, she was 20. Everyone said we were too young. She went back to school and ended up living her "college years" while we were married, even though she was 3 or 4 years older than her friends. Definitely have had our ups and downs, mostly due to financial circumstances (which is what causes most fights in most marriages....well that and sex).
We were married 6 years before having our daughter (who is now 15 months old). We plan on having another soon. We've beaten the odds thus far by marrying young and sticking it out. Maybe we're both just stubborn
Others in some of our past situations would have gotten divorced i'm sure.