In less than a week, I now know two people who are engaged. I knew them both in high school (circa 2007).
Why? I mean, it's great and all. Marriage is awesome. But if you're younger than 20 it's a little crazy. It's madness to me. I just feel that at this age, you have no clue what you want. And there's still a lot of living to do.
My philosophy is that you never really know what you want. But marriage is kind of a HUGE decision.
You're still in school. Go to parties. Start a shitty band. Get a tattoo. Go to Europe. Graduate. Then after that, you can get a job. And once it's all stable, you can get married. That's what I've known.
Not to bash anyone that gets married young or while they're still in school or anything. Sometimes it works out. And a lot of times it doesn't.