My sisters boyfriend is 5 years older than me, and i am 20 years old. I like older men because they act more mature than guys my age. Well, she was out one day and he came by the house to visit her and i told her that she wasn't here, and he asked if he can wait for her there so i said sure. I get turned on easily, cuz i am like a sex machine. Just by looking at him and imagining him naked, i was getting turned on. I told him about it because i wanted to do it so bad with him before my sister got home, so i did, and he agreed. We went to her bedroom and we had the wildest sex i have ever had. She does not know about it, should i tell her now that i regret it, someone please help!