34 now, been on meds since getting diagnosed 2.5 years ago, I failed calc 2 because I bombed the exam (luckily I could rewrite) and scraped by a few I had zero interest in. Also still recall one prof in my last year emailing me asking why I hadn't turned in assignments, I totally did cost-benefit analysis on every course to see what was worth doing and what I could get away with and still pass, helped that 70-90% of your final grade was the final exam in a good chunk of my courses. Uni is where my maladaptive coping mechanisms come from, I binged, used self induced stress as a motivator, would pound a pot of coffee myself during exams, only developed a lot of these skills relatively recently with medication and 4 years of therapy. No wonder I still struggle with internalised negativity to this day.

In retrospect I don't know how no one ever suspected or suggested it to me, I'm moderate combined and it's caused me physical, financial and relationship issues in my past, I always just got called "aloof" or "head in the clouds", I masked hard but that caused my issues outside of work and school, only have so much energy. I'm also certain one if not both of my parents have ADHD which might contribute to the late diagnosis, ADHD behaviours are totally normalised.