Curses of Scale - Evercharm Series

Sixteen-year-old Niena wants nothing more than to attend an elite bardic college, but when the dragon that shattered the empire awakens again she finds herself on the run, through the fey realm of Fairhome, to the city where she was born. On her trail are her army veteran grandfather, thrown into a commander's role he doesn't want, the lord of the fairies, trying to steer her to his own ends, and the husband she won't meet for fifteen years.
If she kills the dragon, she'll save everyone she holds dear. But if she kills the dragon, she's cursed instead to become it.