This really resonates with me because it was a very similar story with one of my projects (a $SHELL -- a bit like Bash et al). I started it as a short "what if" project and was really surprised at just how much already worked after only 3 weeks.

I think it's a great lesson for hobbyists: don't worry about perfection. Just POC something and if you're still passionate about it after 3 weeks you can always go back and tidy stuff up.