Please dont feel bad about this,
I will also ADMIT that I too feel like this at times. exspecially with pre puberty transitioners. But more for just having hawt bodies and those realy curvy hips.
I read somthing somewhere, that the girl all the guys want, is the girl all the girls want to be. Ok i know its not exacly accurat but..
envy, is somthing that everybody has in various degrees, over variouse things, people get jelouse of other people all the time.
Dont feel bad about somthing that every human exsperiences, you ARE HUMAN after all.