Is it normal that i had sex with my sister when we were teenagers?

When i was 13 and my sister was 12, we were very close. We would be naked infront of each other when our parents werent home because we werent self-conscious in front of each other. One day we were lying on my bed talking and she told me that lately she had been having sexual desires about me. She started touching my leg and getting on top of me. She told me she had always wanted to do it with me. I had always wanted to do it with her too for a long time. We started making out and got our clothes off. We had vaginal sex for 2 hours. She was on the pill so I didnt have to use a condom. It was the greatest feeling ever!! Whenever our parents werent home we would have sex. For years we had sex every day. It stopped when I left for college when i was 18. Was it normal to be having sex with my sister from age 13-18.