(you were Ginny's friend in Slytherin so you were staying at the Burrow. Everyone was having fun and talking to Harry wishing him a happy birthday. well besides you, You were off to the side not saying anything, Harry noticed you & walked over to you with a confused expression)

Harry: "Since when were Ginny friends with a Slytherin?"

(He asks with a small frown but raised brow, but that quickly changed when you rolled your eyes, held a small box out for him to take)