Personally, I think it's too young. I'm 18, my girlfriend is 20. We're both in college, and we've been dating for over a year. I'm not interested in getting married anytime soon. There are good and bad examples of early marriage in my family. My great aunt and uncle married more than 40 years ago when he was 19 and she was 14, and they were happily married for a long time. Until he died a few years ago, in fact. On the other hand, my parents have been married for nearly 30 years and they're not happy. My dad blames it on the fact that he was too young when he got married right out of college (he was 22, she was 21) and he advises me to wait until at least 25. After having to live with my parents for so many years, I can't easily dismiss that advice. My girlfriend shares my viewpoint to an extent. She doesn't want to wait quite as long as I do, but in her family, her older brother got married at the age of 19 and divorced 5 months later.
Really, I think it depends on the person. Sure, it's possible to get married young and be happy. That's just not for me, but it works for other people. I know several people I graduated high school with who are now married and/or have kids. I just couldn't imagine doing that before you even hit 20 years old. But it's do-able. IIRC, the average age of a man getting married is 27 in the US, and the average age for a woman getting married is 25. Honestly, I think your marriage has a must better chance of working out if you wait until your mid-20's. By then you have a better grasp of what you want in a relationship, and what you want out of life. At least that's what I've been told, and I know I'm not yet certain on either of those issues. That's why I know I don't want to make that kind of commitment anytime soon. Sure, you could get married young, and then develop towards the same goals together. But it's more likely that you'll find yourself headed towards different ones. I know at least half a dozen friends around my age, and no older than 22, who have gotten engaged, only to break it off.
Like I said, it depends on the person. You are, however, putting yourself at a significant disadvantage. Young guys like us have only been a part of the serious dating scene for a couple of years. I think if you go through several relationships, over the course of several years, you'd be much more likely to know what you want in a relationship, and how to recognize it when you find it. Getting married early is like shopping for something, and buying the first thing you find instead of shopping around.
Anyway, good luck!