OCD about Sexual Experience as a kid HELP

I'm honestly not sure if this is the right place but the thoughts feel like my pure ocd. I would almost consider myself BI, but straight leaning, and when I was 12 I had a gay experience, I don't want to get into details, but he was kind of like my step brother, but he wasn't, our parents dated, and we share a half little sister from them, but now I'm scared it was really weird that I did this, I'm 17 now, and I just chalked it up to being experimental, because I was a confused 12 year old, but now I'm scared people are gonna see it as almost like incest if anyone found out, but at the time I didn't think it was like that, we aren't related Iin any way, not even step brothers, but we share a half sister, and I've been feeling really depressed about this, and it totally took away the pocd I was having before this worry, I just need to know if I'm messed up person for doing this.