How do i ruin her life?

i have become close to this girl at school, but today ive only just realized, that she is an absolute b*tch who is a spoiled brat. she is 13 by the way. she always criticizes me for thing i wear and she is different round other people when she's with me than when its just us too. i'm sick of it. i want to ruin her life. she always texts the boy i like and lies about it. she is a lier too. all the boys think shes 'fit' or 'sexy' but too be fair she is naturally very pretty. i am just sick of her i want to ruin her life so that no boys will ever fancy her and she gets what she deserves. she always texts other people boyfriends and goes in a mood if she doesn't get what she wants. PLEASE someone tell me how to ruin her life, thanks!