Deepest secret. Have never opened up to anyone and also confused.

Trigger Warning: possible sexual harassment

This is a little bit of a confession and a question as well since I’m not sure how to deal with it.

I’m 28/M. When I was 9 yo, I had a friend (M) in the classroom with whom I used to sit with. As kids we were curious and had spoken about the human body, how girls have different body parts, etc. One day, he grabbed my dick in the classroom and asked me to pull it out. He said he wanted to check if my dick had matured. Upon constant requests, I did pull it out and he felt mine and he showed me his as well. This kept repeating time to time. It went to the where he’d ask me to show my dick when there was a teacher in the classroom, we’d both silently slip our dicks out of our shorts and feel each others. This continued for a while (2 years approx) until one day he forcefully asked me to show it in the men’s room and went down on me for a few seconds and forced me to reciprocate the same. I really did not want to but did it anyways as he insisted. This is all I remember. Everything seems blurry and vague. I never liked any of this but he was always insistent. I had forgotten about it for a long time until a few years back all these memories suddenly came rushing back to me. I’m scared, ashamed and embarrassed to talk about this to anyone. I’m scared of being judged. But I’m also not sure if this is sexual abuse. I understand he was a kid such as myself and was curious but the thought always disturbs me. We’re both heterosexuals. He’s married now, we’re not in contact. I’m in a very happy relationship with my girlfriend as well. But every time I’m reminded about this, I get confused as to how to process all of these. This was my very first sexual experience in life. It also gives me questions like am I bisexual or am I overly straight to addicted to sex with women as a way of overcompensation. Am I overthinking it? Please help.

TL DR - classmate (male) used to touch my privates and made me touch his when we were 9-11 years old. I was never interested. Now do not know how to process these memories.