The demi witch

Stella Rose Black is Sirius Black's half sister. She is friends with the marauders and the seven plus alot of other people.
She is going into her 5th year at hogwarts and she is surprised to have lasted this long at one school.
No one at hogwarts knows she's a demigod and thats how it stays for 5 years until her friends from camp half blood come to hogwarts. Now she must explain the other side of her life to the two groups of friends.
(plzzzz read and soz for any gramer or spelling mistakes I really dont care for them)