I haven't been absorbed in a book like this in so long! Oh my god it was phenomenal and I just flew through it. The first chapter is slow and not very interesting, but just read it until the end and things will pick up pace very quickly! This reads like a manhwa, in the best way possible. The girl who works as an attendant for a bitchy mistress, then catches the eye of the Crown Prince and moves into his castle. HOWEVER! this is NOT a story where the knight in shining armor saves a damsel in distress! not at all my friends! She's chosen as the prince's companion (someone who trains and studies alongside him) until he takes up his duties and she goes and joins the army. Our protagonist is fierce, strong and determined. She's not perfect, her heart keeps betraying her, but she never loses sight of her ambition! 
However, at some point, it was getting ridiculous how every man she met instantly fell in love with her, making all the other men jealous. 
Other than that: such an exhilarating read. Celestials, royals, dragons, immortal kingdoms, magic, archery and swordfighting, romance, it's all so good!