Is it normal i fucked my cousin?

Ok, So when I was 16 I went to my cousins house ( she was 13) and our parents had to go somewhere so we were alone. So she looked cute in her short shirt and her very small shorts. And the time we had no air conditioner so she said I'm hot and took off her shirt and shorts ( leaving on her underwear and bra) So she asked me to take off my clothes if I was feeling hot so I did. I then got a boner (because she looked so hot in her underwear) and she said "I've never seen a dick can I take a look at yours? So Naturally I said yes and took off my underwear then she took off hers and then she was begging for me to put it in so I did. We fucked for about 10 minutes and I yelled "IM CUMMING!" and I came in her. We got scared and we put our clothes back on and we went to her room and I started to Play with her breasts while we were making out, then our parents came and I left.