Stone Girl

At almost fourteen, Myra shops in the fat girl department. No one, least of all her mother, will let her forget it. But Myra finally finds a friend who wants to spend time with her and doesn't mind being seen with her.
But is it for real? Or will her new friend be like all the other kids, and make fun of her for being fat? Why does she have to choose between friendship and doing what's right?
And who is really answering the notes Myra leaves at the statue she calls Stone Girl?
Is the writer a friend or a foe?