Might I suggest starting with a smaller project first? That way you can develop the requisite skills in order to bring larger projects to life.
Most larger modding projects end up never getting finished (or are finished in a sub optimal state). By taking the time to work on a few smaller projects (adding items, NPCs, ect...) you will have a better understanding of what is needed to successfully pursue your larger scope projects.
Obviously, I do not want to dissuade you from trying, but I have seen a great deal of modding projects remain incomplete due to the lack of cohesive fundamentals.