I'm 18 and a girl and my boyfriend is 16. A lot of my friends dissaprove and its getting me down, what do you think?

Is it unusual? Yes--normally at your age, girls are a little more emotionally mature than guys, so they tend to date guys who are a little older (since they're closer to the same level of emotional maturity). Does that make it wrong? Not at all. As long as you're both happy, it doesn't really matter what anyone else thinks--your ages aren't so far apart that it's inappropriate, and it could be that he is unusually mature for his age. Don't worry about what other people think--just enjoy what you've got while it lasts.