The Amiestrin Gambit. The King's Daughter, #1

Ellis Dantreon is barely fifteen when she learns that her father--the king of Jenear--has decreed that she's to be trained as a soldier.  Thrust in among the others at the newly reopened War College of Amiestrin, Ellis must earn the other cadets' respect and trust. Not all of them are pleased at having a girl thrust among them. Ellis has to choose which ones to trust, sometimes pushing back against her instructors' urging as she does. But most of all, she must deal with a world far wider than the one she's known.
That world will shape her future, for the Gifted whom her meager staff have always considered myths prove to be very real indeed. Those people want very much to influence the course of a future Jenear. When it comes time for her young brother to take the throne, the seers among them believe that Ellis will decide whether her younger brother lives or dies, or if he'll be replaced by another claimant to the throne altogether. And hidden among the cadets and staff, some of those Gifted have arrived at Amiestrin...