Of Giants and Ice by Shelby Bach

Rory Landon has spent her whole life being known as the daughter of a famous movie star mom and director dad. So when she begins a new after-school program and no one knows who her family is, Rory realizes something is different. After she ends up fighting a fire-breathing dragon on her first day, she realizes the situation is more unusual than she could have imagined. It turns out the only fame that matters at Ever After School is the kind of fame earned from stories Rory thought were fictional. But as Rory soon learns, fairy tales are very real—and she is destined to star in one of her own.