My ADHD diagnoses was very late in life, I only got an official diagnoses because in my first year of college because I would get accommodations which would allow me more time and less distractins during mid-terms and finals.
What actually happened was I started to learn about ADHD and it was nothing like what myself or my family thought it was, I still don’t have a complete grasp on it. The biggest thing I have seen in almost every single person with ADHD that I have spoken to or read about spent a long time, usually years thinking that If they knew they had ADHD earlier life would have been different.