Met my wife in highschool and got married right out of college. We are now pushing 40 and are still happy and content. We were lucky, we grew together and in similar ways, but we also just knew when we knew. We even had twins a few years back and even the stress of that didn't destroy us.

We (hopefully) still have many years together and maybe things will break down, but, so far, neither of us regret marrying so young.