Intro to Sarafina Carmen Weasley

Sarafina is the older twin sister of Ronald Weasley. Even though she is only 4 minutes and 31 seconds older then Ron. She, Fred and George never let him forget he is the younger twin. She has a Siamese cat called Yuki who is only year old when Sarafina first went to Hogwarts. Sarafina is the only one who can really tell Fred and George about. What house is she in? Does she help protect the stone from Voldemort? Which is her best subject? Picture of Yuki on cover.