College. And I think I actually developed co-morbid mental illnesses (depression and anxiety) that led me to finding out the root cause (ADHD-PI).
More info: I'm pretty positive (through internet rabbit holes) that I was what some in the psychology community call "twice exceptional". I fuckin' crushed school all the way into (and most including) college. Because of that, my numerous (in hindsight) obvious symptoms were ignored/let go because I was "successful". The closest is 1 teacher of a different class in my grade (not even my own teacher) told my mother I should be tested for autism because of how upset I would get at deviations from plans (again more likely my ADHD). That all came crashing down when I just... fell apart one semester of college. I gained weight and was at my heaviest ever (and I'd never been skinny) and I failed my only class in all of school (still the only one). If I hadn't been encouraged by my partner to get help (and then do some self-diagnosis to fight my way to the ADHD test)... let's not go there.
Still really struggle with things that I never developed healthy coping mechanisms for because instead I just... lived with them most of my life (and all of my formative years).
Its made me completely adverse to making plans. Like, I looooooathe making plans any further out than a few hours from now, because otherwise my life is rendered inflexible and anything that could upset my plans are means for monumental emotional turmoil.