I live with two people with ADHD and I'm not seeing it. The OP describes giving up too easily for hard tasks, which is fairly common (I mean I have it) without any other indications for ADHD.
I have ADHD and while giving up easily is an indication for ADHD I have also a washing list of other symptoms, e.g. switching to a new hobby every other week, having sudden urges to google random things because my brain thinks it is of utmost importance to know about it RIGHT NOW, inability to maintain concentration if the thing I have to do doesn't interest me - but hyperfocusing on things for days on end if they interest me etc etc
ADHD is much more centered around concentration than just giving up easily, I guess.
