(SPOILER)The thing that confused me was whether Petunia could of adopted some magical powers as well as Lily, because why would she enroll to Hogwarts and receive an returning later stating she is welcome to join? I wonder if Dumberdore knew that she possessed ability to awaken such powers, but lost courage when the time came to board the train...? Surely, Dumbledore doesn't have the skill in magic to help evoke inner powers from such children.
