I did fine through high school because it was easy enough. Studying was hard so I never learned how, just did a good job of winging most things without thinking them through, and being good at eliminating obvious wrong answers meant multiple choice tests were a breeze.

College was.a massive struggle because it required making my own schedule and studying, which I could not do. Ended up being diagnosed in my 30s and medication is so helpful that I am miserable whenever it gets on backorder. It did take trying a few different meds before finding the one that worked without negative side effects.

If you feel like you have a handle on remembering important things and have behaviors that keep your kife running smoothly then medication may not improve anything. But if you feel, or someone you trust feels that medication might help it would be worth seeing a doctor to discuss.

somehow had untreated ADHD

As if the whole diagnosed ADHD movement hasn't only just existed for the last 20-30 years. And really picked up steam with the increase in casual use of Adderall in the early 2000s