I'm fifteen and being a gentleman seems to repel girls. What do I do?

Being young, I'm expected to party and be rebellious, but I'm not. I study, I'm a homebody, I'm mild-(and well)mannered and polite. I grew up more conserved and well-behaved and grew up "old-school" you could say. Now, one of my traits is respecting others, especially women. But this seems to have no effect. The girls I know seem to want the crude, loud-mouthed, sadistic jock types, the ones who focus on and make fun of a brain-damaged person because they slur words. Now, I've always been "the nice guy", but I'm pretty much getting fed up. Does this mean I have to be more crude and less "chivalrous"? Even if I do, I don't think I'll be able to, it's just not in my nature. Some advice is very much appreciated, thank you.