I guess the way I think of it is, you know how you're allowed to use a genre-specific engine, like the RPG Maker series? You should be allowed to reuse code if it's effectively the kind of thing that an engine like that would do. I'm not an authority, but that's how I interpret it. Also the rules are intentionally pretty woggly, and as long as you report it in the "i started early" section, I'm sure a lot of people would forgive you for fudging the rules a little.
P.S. Welcome! ...is what I would say if this wasn't also my first time. :3