Don't be afraid to play around with worldbuilding ideas. It may take a bit of tweaking and reworking to make an idea work the way you would like. If something you try doesn’t work out…so what? Scrap it and try something else. There really are no worldbuilding police to force you to use an idea in your story that doesn’t work for you. This is the time to experiment and see if anything grows from letting your mind wander down unusual paths.
Don't let this stress you. In this series we have talked about a lot of things you may (or may not) want to consider for your world. Remember, an idea does not have to be a stable concrete thing, keep it fluid and evolving into what works for your story. I think you will find that it will change, evolve and reshape itself to support your work. What you had for your original concept may have taken a turn into something completely different as you start getting into your novel. Often, as you get further down the writing path, you may find it changing again. This is not unusual. Eventually it will feel comfortable and encompass what you have written rather than shaping what you will write.
Don't be afraid to reshape your ideas, themes, characters and worldbuilding material. The more detailed and familiar you have become with the world you are creating, the easier things will flow as the actual storytelling and creating process begins.
This is a good time to go back and reread everything you've written and see if there are changes you want to make which will help you better develop the idea. Think about emerging characters other than the ones you've created already. Think about the story-world into which you are gong to put them.
One thing to especially consider is your theme and how you can use it to influence the creation of your world. Don't be afraid to experiment. Everything can be changed. Now is the time to be daring. It's easier to fix dead ends and odd problems in the pre-work than in the writing.