Fourth Wing by Rebecca Yarros

Twenty-year-old Violet Sorrengail was supposed to enter the Scribe Quadrant, living a quiet life among books and history. Now, the commanding general - also known as her tough-as-talons mother - has ordered violet to join the hundreds of candidates striving to become the elite of Navarre: dragon riders. But when you’re smaller than everyone else and your body is brittle, death is only a heartbeat away… because dragons don’t bond to “fragile” humans. They incinerate them.