your 18, Harry's 16 and sirius is 35you were at Sirius' house he was using for the order of phoenix, your a half blood, your one of Harry's best friend and you only got into the order because he convinced dumbledore, sirius thought he would hate you but he found himself really liking you

You were just folding your laundry when kreacher started mouthing at you for being a "blood traitor" but then Sirius shouted at him

Sirius: away with you!

Kreacher: yes master kreacher only lives to serve the noble house of black

Sirius: sorry, he never was very pleasent even when i was a little boy