Based off Claudia Gray's Princess of Alderaan, so I'm gonna use that book's summary:

It is Leia Organa's sixteenth birthday, and she participates in the traditional ceremony where she declares her intention to one day take the throne of Alderaan. But she's much more concerned about the way her parents are acting lately: lots of meetings and late dinners and not talking to her as much as they used to. Eventually she discovers the reason for their secrecy: their involvement in the increasingly organized rebellion. When Leia decides to become involved herself in the fight against the Empire, whether her parents approve or not, she will have to prove to them that she is a valuable asset who must be allowed to take a stand, regardless of the risk to herself. Her stand will also put her at odds with a pacifist young Alderaanian man who gives Leia her first kiss…and her first real loss.

The reign of the Galactic Empire has reached the Outer Rim planet of Jelucan, where aristocratic Thane Kyrell and rural villager Ciena Ree bond over their love of flying. Enrolling at the Imperial Academy together to become fighter pilots for the glorious Empire is nothing less than a dream come true for the both of them.
But Thane sours on the dream when he sees firsthand the horrific tactics the Empire uses to maintain its ironclad rule. Bitter and disillusioned, Thane joins the fledgling Rebellion — putting Ciena in an unbearable position to choose between her loyalty to the Empire and her love for the man she's known since childhood.
Now on opposite sides of the war, will these friends turned foes find a way to be together, or will duty tear them - and the galaxy - apart?