Your question can only be answered with another question (annoying, we know): Why don't your friends like him? If the problem is that he's constantly getting sent to detention, or he hassles other kids, or he's been a jerk to the girls he dated before you came along, then your friends may have a point. While it's true that people can change and mature, your friends may be able to see things about this guy that you, given your current state of smittenness, aren't picking up on. And if his past bad behavior is indeed the source of strife, it doesn't mean you have to rule him out entirely. If you know him pretty well, and you're convinced he's worth the risk, explain how you feel to your friends. They're more likely to give him a chance — and to back you up — whatever you decide.

On the other hand, it's possible that your friends are the ones who are behaving badly. If their problem with him is that he isn't cool, cute or popular enough (or that he's a different religion or race), then don't think twice about ignoring them. You shouldn't let yourself get pressured into staying away from someone you really like just because you think your friends will judge you. It's important to think for yourself — and anyone shallow enough to give you a hard time for dating a guy who is different isn't much of a friend in the first place.