I have went through this all throughout my high school years, but you know the only reason why this girl is saying things like this is because she has her own insecurities. You are clearly a pretty girl and you take care of yourself, and girls like that usually get on with that behavior out of jealousy, or they are not receiving enough attention - either at home or from their peers.
The best thing to do is just ignore and laugh at the situation; don’t let a person like that make you feel like you are vulnerable because that’s exactly how they want you to feel. Do your own thing and ignore the crazy bitches 
