Magic Lessons — Justine Larbalestier

Fifteen-year-old Reason Cansino has learned the painful truth that she--like her mother, grandmother, and new friends Tom and Jay-Tee--must face a choice between using the magic that lives in her blood and dying young, or refusing to use the magic and losing her mind. Now a new threat leaves Reason stranded alone in New York City, struggling to control a power she barely understands. But could the danger she faces also hold the key to saving her life?