i can’t forgive myself. how do i move on and live my life?

There may be some triggering topics I understand if this gets taken down.

I (20F) made a terrible and risky mistake at the age of 18-19, I live in shame and guilt over it. Basically through an online peer group I met someone who was 16 when I was 18. Two grades apart, 2-2.5 years apart in age. We flirted, I wanted to stay friends but that just didn’t work I guess. We “dated” (hesitate to call it that) for a few days before I cut it off because I didn’t feel right about it. We were in two different spots in life. I regrettably said maybe in the future.

This person didn’t handle it well and I know part of the reason I stayed so close in contact with them despite feeling uncomfortable was because of their talks of suicide online. They were obsessed with me, it was scary looking back and how I didn’t put any stop to this like I should have. We talked about how I didn’t like them numerous times as well. I liked an dated other people.

We did talk and write about NSFW topics which I wholeheartedly regret. We wrote with fictional characters, never about ourselves or anything real sent. This was risky and my thought process at the time was it was fictional and we’re close in age, plus I wasn’t attracted to this person like that so it’s okay.

Things got better at least, for a bit. We were best friends until I realized at 17/19 they still had very strong feelings for me and expected a future together. It finally got nailed into them nothing would happen by me. I talked with them about the NSFW stuff and they said they weren’t harmed by it. Despite that, I realized I couldn’t do this anymore, I didn’t want to date a teenager or one to like me. After a few weeks I sent them a message saying I was ending the friendship, they tried to convince me to come back and I almost caved until I put my foot down. They’re blocked on everything.

I confessed everything to the people in my life. They say I did nothing wrong but my heart feels otherwise. I was older and should’ve known better. I’m doing lots of therapy and waiting on an OCD diagnosis because this event has centered my life I suppose. I understand better about maturity gaps and power dynamics than I did before. I didn’t want to hurt this person, I was told I didn’t but I can’t believe that. I feel I only wasted their time staying friends. Two of the therapists I had said I was emotionally abused actually, which I’m struggling to accept.

I guess why I’m here is asking where should I go from here? Can I ever forgive myself?