I made did something stupid at 15 and it’s been on my mind for years

So when I was 15 I had a big problem with pornography and stuff like that cause I was a teenage boy with ADHD ( I don’t know if adhd had that much to do with it but Ive heard it does) and eventually I wanted to like try and talk to people for this but I wanted to do that with people my age and so as you can imagine I joined questionable servers on discord I saw a lot of things but at one point I ended up talking to someone that was younger than me by three years and for some reason I thought “oh it’s ok they are near my age so that’s fine” which is wrong and I’ve learned then so after a few messages we both said we where bored and then she sent me a spicy picture and I was supirsed this was only after a few images and when she did that I stopped and I never talked to her again I never did anything like that again and I began to think about it I began to feel guilty for it I remember not being able to sleep for days because of what I did I regreted it I felt like a fraud around my friends and family and I was just haunted by it and I still am I still feel guilty I feel like an idiot and I never should’ve done that I feel the guilt I have from doing it 5 years ago