Finding Her Feet by Eve Ainsworth

Most of the time, Lily wishes that she could just disappear. But during a game of football in PE, Lily's teacher spots her natural talent and invites Lily to join the local girls' team, where she starts to make friends with some of the other players. Finally, she thinks she's found a place where she fits in, but will a vicious argument with one of her teammates put that all at risk?