Moonstone: Unbidden Magic (Volume 1)

Allie Emerson is the girl voted least likely to save the world. At Peacock Flats High she can barely handle the bullies and drama queens; her mom's a loser and Dad's a no-show; so when an elderly neighbor gives her a magical moonstone necklace and strange thing start to happen, Allie can't quite believe she's meant to battle the nasty Trimarks of the world. Book One in the popular Unbidden Magic series.