I remember hearing once that, if your MVP(Minimal viable product) can't be finished in a month, you're probably doing it wrong(Believe it was a Youtube channel called "Extra Credits"). Working on graphics, or expanding mechanics, or adding music, etc. It's okay if you don't want to release your game without polish or nice a nice art style or such. But it's important that you get a jist of your scope, and can see your core machanics in action, before anything else. It's even okay to decide at that point that you don't like your game at that point, because you will have learned something, and gained new skills from the experience. Fail faster, and you will see improvement.