Eon: Dragoneye Reborn by Alison Goodman
I've had this book on my shelves since 2008, when it first came out. It reminded me of Mulan, girl passing self off as boy. Not that I've ever seen Mulan, but I'm sure it's on the shelves somewhere. Anyway. Eon is in training to be one of the next Dragoneye apprentices. There are 12 dragons, each corresponding to a line on the compass, who chose a Dragoneye Master to wield it's power. The Dragoneye Master are trained fighters and they use the magic of the dragon to control the weather and protect the villages. They are also very rich and powerful as they have the ear of the Emperor as well. Twelve 12-year-old boys are chosen each year to train with a Master and eventually take his place. The families of the twelve can be assured of a secured near future. Those not chosen can be assured of ruin. Also, women are not allowed, keep out. So, Eon, who is this sixteen year-old girl who used to be on the streets, is posing as a 12 year-old boy. Her master, Heuris Brannon, has pledged pretty much everything he owns, including his reputation, on her being chosen. If she fails, the whole house of Brannon fails. If anyone finds out she's a girl, the whole house of Brannon fails. No pressure. Many twists and turn and lots of intrigue, very well researched.