You have your answer, they're "teenage boys" not grown men who understand what real beauty is. It's not hair or looks but personality. Don't worry about it, first priority should be school. That right guy will come and he'll be mature and remember, you're the only person that it should matter to, be happy with yourself. Your curls are beautiful.
Also, sometimes it really is just a personal preference thing. You can't crucify someone just because they don't like X, Y or Z. Whether or not they act on that preference is what says something about someone.