my first thaughts were what is the schooling doing about it, since it is such a young age. if the school refused to do anything or says they cant you need to take it to the school board, maybe go to them with your friends and their parents at their next meeting to really stand out as a group against whats happening. and if they dont agree or do anything about it from there it could become a legal issue actually. becasue the school would be descriminating against her. or just poorly opperating an education facility making an unsafe enviroment for their students. if it were to go that far you could sue the school district
my cousin almost did when she was in middle school. my uncle ran the local tv station and she had her own show interview public figures, musicians and things like that. kids in the public school made fun of her and the teachers joined in. luckily my cousin didnt sue them for all they had. instead they made an agreement to pay for her to attend a private school in town for the rest of the year ( the top midle and high school in the state) after that year her parents kept her there and paid out of pocket to keep her there becasue of the amazing education she was getting.
but other than that make sure to keep her attitude in a good place. let her know that the childred who pick on her are only missing out and when she truely feels that way it will show and the other kids will notice and bejealous of her happyness.