13 gifts - Wendy Mass

When Tara steals the school mascot, a goat, in order to make some
friends with the popular crowd, she gets herself in a heap of trouble.
Her parents decide that instead of going on holiday with them
that summer, she must go and stay with her aunt, uncle, and bratty
cousin Emily in Willow Falls.
Tara thinks it's a good time to start over; she'll be turning 13
after all, so she might as well make the best of it and perhaps even
attempt to break out of her shell (in a non-criminal manner).
What Tara doesn't know is that this charmed town has something big
in store for her on her 13th birthday. It's not a typical birthday.