Is it normal on what i do sometimes?

Hi, I have recently found out, that my sister has been acting kind of funny around me. So, the other day, I went to the bathroom, and when I got out, she was standing next to the door. (Shes actually my step sister)She just waved laughed, and gave me a casual "Hi." I walked into my bedroom to get dressed for a family reunion later that day... And she was watching me. I had just taken my pants off, down to my boxers, and my shirt. She walking in rubbing her vagina, with her hand down her pants. I looked at her funny and asked her "What are you doing, Gretchen?" She just smiled in reply. I looked at her, confused, and she started rubbing my penis with her other hand.... She then pulled down my pants and started to give me a blow job. She then got fully nude, as I was, and with her own hands, inserted my penis in her vagina... she was moving in a swaying motion, pleasuring herself, and then left after about 10 minutes or so. Is this normal?