I do not understand why people hate incest so much.

Today, when I was at a party, I had sex with my cousin (who is a year older). I was surprised when she came up to me and wanted to fuck. We have never been close, but we have always been nice to each other. We only talked a few times. She kissed me and said she had always wanted to try incest because it was so taboo and she thought it would be nice to fuck a family member in the secret. Before that, I had never slept with her as she was always in a relationship. I haven't had a girlfriend for a few days, so we f***ed in secret, but it was so nice and I loved her pussy. And I don't see what's wrong with that either, we're adults and we can do what we want with our bodies.