In particular, Cynthia's Voigt's books have the same characters who age, as do Madeline L'Engle's books. Ann Rinaldi's historical fiction books vary in the heroine's age. The Face on the Milk Carton series ages. Those are just some that I know have college age characters. All, A Tree Grows in Brooklyn, one of my favorite classics. Ooh, and Little Women and Little Men.