Tricky situation

This is probably going to be a difficult post, but I need some help finding a workable solution. I’m a foster kid myself, I’m not in touch with any biological family, and I moved on from that a long time ago. At 18, I got pregnant from rape. I had no early symptoms and an irregular cycle anyway, and no regular medical care anyway, so didn’t know until far along in the process. I didn’t and still don’t want kids and it would have been a bad situation to bring a kid into anyway, so I found the best closed adoption situation I could and then moved on afterward. I barely saw the baby and never held him. I’ve never felt a connection and it was just a very unfortunate situation that I did my best to work with. I was assured that I would not be contacted and that my identity would be kept closed. Now, I have been contacted. Ironically, my partner got us DNA tests for Christmas several years ago and I felt odd about it at the time, you hear stories, but I figured the chances of any of my biological family joining the same database was low since it wasn’t one of the more known companies. No bio relatives aside from some very, very distant cousins popped up, so after the novelty of the results wore off, I forgot about it. I got a message from the kid I put up for adoption a few days ago. He would have turned 19 this last year, so I suppose it makes sense that he would be looking. I already know I don’t want a relationship. I don’t have medical information to pass on or information about the other parent. I have a few vague memories of my parents and their names are on my birth certificate, but no contact info or info about other living relatives. I reached a point as a teenager where it no longer really mattered and I never went looking. I know it sucks, I’ve been there, but honestly the kid was always way better off without me and that’s probably still true. I have myself together these days and I don’t have anything to hide from anyone, but I don’t think I can give the kid what he needs from me and what I have to say will probably add more hurt into the equation. I just don’t know what to say that’s going to be kind as well as firm about my boundaries. Apparently how I feel about my foster situation is atypical, so I can’t even go off of what I’d want for myself in the same situation. Help?