Hunting Dragons. Supernatural Romance

Eighteen-year-old Rima enlists in the fight against dragons after an elf tells her that her future lies with the army. She believes this to be true. After all, the dragon that they are hunting is the same one that had killed her entire family. Life in the army isn't too bad. She gets a roof over her head and three meals a day.  Except she has two big secrets that she needs to keep hidden by any means necessary.
Her first secret is that she's a woman in an army of men and she shudders to think what they would do to her if they find out. She serves a bloodthirsty captain who is as hateful and ill-tempered as everyone warns her that he'll be. It is difficult to keep her secret when they spend so much time together, when her sole purpose in the army is to satisfy his whims and carry out every task to cross his mind. She grits her teeth and does everything that's needed of her.
She really shouldn't be falling for the terrible-mannered captain, not even when he starts warming up to her and shows her that there is kindness and compassion under his cruel mask, when he cradles her face and tells her to trust him. She thinks he might have figured out her secret, but that's fine as long as he doesn't figure out her second secret. Rima's second secret is even bigger than her first. You see, Rima isn't human at all. Rima's second secret is that she is one of the things that they're hunting.
Rima is a dragon.