The Magnolia League (Magnolia League, #1) by Katie Crouch

After the death of her free-spirited mother, sixteen-year-old Alex Lee must leave her home in northern California to live with her wealthy grandmother in Savannah, Georgia. By birth, Alex is a rightful, if unwilling, member of the Magnolia League, Savannah's long-standing debutante society. She quickly discovers that the Magnolias have made a pact with a legendary hoodoo family, the Buzzards. The Magnolias enjoy youth, beauty and power. But at what price?

As in her popular adult novels, Crouch's poignant and humorous voice shines in this seductively atmospheric story about girls growing up in a magical Southern city.