Your sister is a creep. Whoever was handing out personalities sure had fun when it came to the 2 of you. She isn’t in your house, you waited 1 whole hour after those footsteps went outside to make sure everything is good.
But if she WAS in your house she’d never let you find out. You don’t even know where she lives, but you would have loved to visit her at least once a week. How nice that would have been…