Funnily enough, my best friend from uni messaged me recently asking if I thought she'd ever shown signs of ADHD as 2 separate people had armchair-diagnosed her at work! I said to her I hadn't noticed anything but even if you have ADHD, you've gone through life fine, had a successful career, loving boyfriend and friends and family who love you so you don't need to take a test for anything if you don't want to and if people have made you feel uncomfortable about it. Exactly as you say, what would a diagnosis acheive?