Sister Surprise

One Saturday morning, when I was 13, I was drying myself after a shower when the bathroom door opened and my 11-year old sister stepped inside. I was so surprised that I dropped my towel and stood naked before her. She just stood there staring at my dick and the black hair around it. As I attempted to pick up my towel she asked me if she could see it again. I dropped my towel again and she then asked if she could touch it. I said yes, but only if she got naked too. Two minutes later she was also naked. She didn't have any tits yet, but her nipples were puffy and she had a bit of dark pubic hair above her slit. As she started to hold my dick it started to get hard as she ran her hand over it. Right then we heard a noise in the the room next door. We both scrambled to get our clothes on and exited the bathroom very quickly. Neither one of us ever mentioned it again.