Help, I'm not allowed to wax my thighs!?

I'm 13 years old and my mom has finally allowed me to wax (after a lot arguments, crying, etc.).... but only below my knee! Since I am on a girl's running team our uniform is slightly above the knee, and this shows much of my thigh hair, which is VERY thick and dark. Not only does it look unsightly, but I also feel embarassed because even though people don't say anything, they often look at me weirdly or disgustingly. No matter what I say, my mom is not allowing me to wax, because apparently all the hair above my knee will gradually fall off, like it did to her when she was 17. Now this is very unfair, because naturally, my mom has barely any hair, and I have very thick and dark hair. What should I do so she'll let me wax my thighs?