When I came home from school....

So this happened like a week ago. I came home from school and I notise that no one was home. You could tell. the curtains were covering the windows and the garage was closed. So I get my key. I am about to unlock the door until I look at the window right by the door and i see my sister looking at me. She looked very creepy! I screamed and i almost punched the window. I told her to not do that again but I'm 100% sure that she didn't hear a word of that.