Is it normal that i let my little brother watch me masturbate?

A few years ago I was home with my younger brother while our parents went out for dinner and drinks with friends. My brother who was 12 at the time had gone to bed so decided to go and have a shower before also going to bed. After showering and getting dried I went to my room and relaxed on my bed with only a towel around me and watched TV. As I was laying there I began to play with my pussie and after a few minutes I started to get right into it and going for my life. Just as I opened my eyes and looked up at the door to my room my brother was standing there watching me. At first I was a little shocked but I was so horny and I didn't want to stop so I kept on playing with myself. I told him that if he wanted to watch then come over and sit on the bed so he did. As I continued to masturbate and finger my very wet pussie he couldn't take his eyes of me and it actually excited me so much that I had multiple orgasm's. Since then I have let him watch me masturbate using my dildo a few times more and have both promised to keep it our little secret.