aprilynne pike -- wings

Wings is the debut, young-adult faerie novel by author Aprilynne Pike. It is the first of four books about a fifteen-year-old girl who discovers she is a faerie sent among humans to guard the gateway to Avalon.
Wings was released in the US, UK, & Canada on May 5, 2009, and became a New York Times Best Seller in its first week of sales,[5] reaching #1 on the Children's Chapter Books list in its second week.[6] It was also a Publishers Weekly Bestseller[7] and made Pike the best-selling non-celebrity children's author to debut in 2009.[8] Wings went on to become an international bestseller in 2010.[9]
The sequel to Wings, Spells, was released on May 4, 2010.[10] The third book in the series, Illusions, was released May 3, 2011. The series concludes with Destined which was released on May 1, 2012.