little sister and me

This story is 100% real… I have changed the names to protect me and the others involved in the story. I will also keep our ages a secret too. This happened to me about 4 years ago and has continued to happen. If you guys like this story I will share some more of my stories with you.
It was a cool summer day in June, it was me my sister my mom and grandmother at the restaurant we always ate at on Thursdays. It was nearing the end of breakfast when I started to pick on my sister for her grades at school and then she said something that shocked me and made me shut up real quick. She said that I better stop or she was going to tell mom what I used her computer for the night before. What she was alluding to was that I barrowed her computer to look at porn, and I must of forgot to delete the history. The reason I was looking at porn was because I hit a dry spell in my sex life and needed to get off. My sister was a couple years younger than me and she was one of the cutest girls in our school. She was athletic; she played soccer, hockey, and softball. She was about 5 foot 5 and weighed about 140. Most of it was in her ass. She got that from playing hockey. She had nice thick thighs that went into a nice tight firm ass. She had nice sized tits, I think they were 34 b. she was a well-built girl that all my friends made joke about her being good looking. So after she told me she knew what I did I shut up until we got home. My mom dropped us off at home because she got called into work and needed to get there fast. All that was running threw my head was how I was going to get my sister not to tell my mom what I did. It was just me and my sister home and I decided that I was going to confront her about it. So went up to her room and knocked. She said that I could come in, so I did.