I’m 40 and just started medication for ADHD. When I was in school there were some kids diagnosed with it, but they were the kids bouncing off the wall. I was just told I was a daydreamer, lacked concentration, just needed to focus more because I had so much potential if I could do the work. Instead I just skated by as a B student largely on testing well, but not turning things in. That’s not to say you do or don’t have it, just don’t assume you don’t have it because no one ever mentioned it when you were young.