kitten is right...bullies and people that do what this girl is doing are actually insecure...call it trying to psyche out the competition. It only works if you let it. Unless she does actually come at you physically, take her teasing as a challenge and as kitten indicated, if even bothering to give her (the girl teasing) the mild satisfaction of bothering to respond, not so much as ask as state that you know she is only teasing you because she knows you are the better rider. For most, it does make them blink when someone stands up to them, instead of getting upset.
If, however, she EVER comes at you physically, then you need to let someone know.