Be careful with people's diagnosis online. Everyone has some characteristics of OCD, AHDH, etc. so you need a licensed therapist diagnosis you.

So it seems you are mostly worried that part of your sending of porn went to someone underage correct? You aren't in charge of other people. If someone lied about their age how could you have known? You aren't checking IDs (nor should you) so it's not in you. Even if you did send porn so what. These people were dedicated to finding porn with or without you. They were going to see porn if you were there and not if you don't. I know I was looking for porn before I was 18. If you were purposely sending porn to a 12 year old to groom them that would be a problem. You were meeting these people and weren't targeting specific people.

You are feeling guilty about what you did. That's okay. You will need to give yourself forgiveness about it.