Mattie and Teag Vann had their wands drawn at the ready as they posed next to a cutout of the famous Harry Potter at Books-A-Million on Saturday. Mattie, a 10-year-old wearing a Hufflepuff robe, is a big fan of the fourth installment of the seven-book series, according to her mother, Colleen Vann. And at 12:01 a.m. Sunday, Mattie and her 8-year-old brother, Teag, would have a new Harry Potter book to wear out.