For a more substantial read than a lightweight vampire romance, give your teen an historical romance by Philippa Gregory. She is an excellent writer who creates wonderfully exciting stories that are hard to put down.
The Constant Princesstells the story of Catalina, Princess of Spain, who has been raised since infancy to become queen of England. With the death of her husband, Arthur, the only way that she can achieve her goal is to marry Arthur's younger brother, Henry. Relying on faith, intelligence, and a sense of destiny, Catalina transforms herself from princess to Queen Katherine. A compelling, unforgettable read.