You are Harry's older sister so you would sometimes stay with the Weasleys when they invite the two of you over.

Now you're hiding in the twins room with Bill and Charlie and the twins to talk about their secret joke shop business plan when Percy walks in.

"Shoo Percy. Leave us alone. And have you ever heard of knocking? That's basic manners for someone who's in the Ministry of Magic. " you scowl as he scowls back at you "Excuse you, you're just lucky I've graduated. Or else I'll make sure to take 5 points each from Gryfinddor. And before you object, I as the Prefect of Gryfinddor has the rights to take points from my own house. " Percy says and starts babbling again.