I'm From Nowhere - Suzanne Myers

A few weeks into her sophomore year at Ventura High School in California, everything is about to change for Wren Verlaine. It''s always been just Wren and her mother, Hannah, but when Hannah receives a reporting assignment that sends her to Greenland for six months, Wren is shipped off to Hardwick Hall, a prestigious boarding school back East. As Wren finally starts to settle in at Hardwick, clues begin appearing about the one secret her mother has ever kept from her - the identity of her father.