Hex Hall by Rachel Hawkins
Hex Hall is a reform school for wayward Prodigium (witches, faeries, shapeshifters, etc.) youth. When Sophie Mercer’s magic draws human attention during a prom night from hell, her estranged Warlock father sends her off to Hex Hall. Unfortunately, Hex Hall isn’t all sunshine and rainbows though; because it isn’t long before Sophie has made powerful enemies, gained a creepy ghost shadow, and has become embroiled in the dangerous mystery of a predator that is attacking students.