This is kind of a reverse What If? day, because today we're asking what to cut.
What if it doesnt fit? After almost a month of world-building, you may be running into the problem of contradictory ideas, things that dont mesh together, or bits that you like but which ruin the mood.
I have a separate page in my notebook for the Dares that I like but which I'm not sure if I want them in the novel or not. Similarly, I have a separate page of "Misfits" for ideas that don't match what I'm planning to do, but which might later. You can put anything that doesn't match your mood into your Misfits file, but in particular (since this is the world building topic), focus on the cultural and social and world-specific ideas.
Look at your "mood words" list and then at your notes and outlines and ideas. Put anything that doesnt match at least one mood word (or a synonym of a mood word) onto a separate page or in a separate file. You may end up putting your misfits into this novel when you're stuck or need some inspiration or when there's an opportunity for them to fit in. You may even, when you get tired of the main storyline, decide that you want a subplot of Misfits, something to give a little comic relief, perhaps, or just an alternative tone to your main storyline.
For contradictory ideas, pick the one that you like best or, if you have no favorite, the one that best matches the mood of your piece. Put the other one into the Misfits file-- you never know when you might be able to tweak it to fit your story after all. Throw nothing away at this point, but organize your world into "things that I know contribute to what I'm trying to do" and "things that don't match but I like them anyway." In NaNoWriMo, you'll probably want to write things you "like anyway" at some point, and having those ideas already there will help.