They may be worried about you taking their spot. If you have the skills to make the squad, the other cheerleaders will accept you. Cheerleading is not about being pretty. It's about being driven, disciplined and skilled.
Once you make the team they will see you around at the cheer functions so you will probably end up being friends with at least one of them. Good Luck!
Trust me cheer girls will think your all that but you will end up being better and prettier then all of them. Go for it!!!!
Then cheer, be confident and go for it. Who cares if you have braces they wont hate you.
make friends with the girls, they're afraid you might want to take their sport or some sort.