Don't despair James. Work on the things you like, as you feel like it, at your own pace. I like to look at it this way; it is a model, they make more every day! I am up to my third Williams Bros. Douglas world cruiser, 3rd Tamyia Skyray, second Trumpeter Kilo sub, second airfix 1/144 737, second 737-800,(even switched from Revell to Zvezda) and there are several others. Not because I didn't like how they turned out, but because I screwed them up before I could finish them. Happens often, I just grab another box of plastic to torture, sometimes I win, more often it is a draw. The important thing though is up until the point I messed it up I was usually enjoying what I was doing, it kept me occupied and engaged and let me imagine what it could be, so while frustrating it was not a lost cause or something not worth doing. And there will always be the "next one".
Ernie