Firelight by Sophie Jordan book synopsis:

A hidden truth.
Mortal enemies.
Doomed love.

With her rare ability to breathe fire, Jacinda is special even among the draki—the descendants of dragons who can shift between human and dragon forms. But when Jacinda’s rebelliousness forces her family to flee into the human world, she struggles to adapt, even as her draki spirit fades. The one thing that revives it is the gorgeous, elusive Will, whose family hunts her kind. Jacinda can’t resist getting closer to him, even though she knows she’s risking not only her life but the draki’s most closely guarded secret.

Mythical powers and breathtaking romance ignite in this story of a girl who defies all expectations and whose love crosses an ancient divide.