23 for me - this year in fact! It's somewhat harder for PI adults I think because there's a long trail of failures that are perfect explained through the lens of ADHD-PI. Even harder with vivid long term memory.

All the school reports that say "James could do better if he stopped daydreaming|looking out the window and focused more". I was lucky I that I came out with absolutely decent GCSEs (mostly As and Bs) but unlucky in that I felt shame and now defeat that I could have done much, much better. College was a write-off, I attempted 3 times but gave in after 3 months each time because the stress caused my inastentiveness in lessons made horrendously boring stoked psychosis which landed me in hospital each time.

A lot of my life seems wasted having not known about ADHD-Pi (and of course my parents and educators), except for programming and computers which not only kept me in some degree sane (I could have been worse) but also led me into a job that seems matched to my traits and with a manager that is willing to overlook my big flaws because he thinks my skills with a computer far outweigh them.

What a journey. I say there's enough to write a book but I've just never got round to it...

EDIT: I've just walked head first into a pole just after pressing submit. Sums up my life entirely.