Becoming myself

Harry is a Potter, or so he thought. After the Hogwarts letter came, he was so excited to actually get away from his so called "family" and become a wizard himself. How should he have known, that he was in fact going to become a witch? And why is his new girl name Katelyn Vinda Black? Female!Harry, Dark!Harry, Slytherin!Harry, Supportive!Snape, Manipulative!Dumbledore