Stepsister caught me with her underwear in my room

My stepsister is a hot teen with long legs and tight curvy ass. I always fantasized about her and stole her panty. One day, she came to my room and saw her panty in my drawer. I told her that I never saw anyone beautiful like she and I want to fuck her in the ass. She was surprised by my answer but then she let me fulfill my fantasy with a promise that I won't steal her panty again.