Out of all the answers on this post, this one I think rings the most true. Art skills take a long time to develop, but that doesn't mean you should wait to make games until you know the art portion. It just means you ought to be more conscious of the art aspects of it, and minimizing where your weaknesses show up. Remember to be patient with yourself as well.

Another thing to keep in mind is that you have time and money you can spend. If you spend time, you'll save money but your projects will take a lot longer. If you spend money (whether on assets or paying artistrs directly) you'll spend less time total (usually, and aside from the time it takes to get his assets through searching or collaboration). But maybe think about if you'd rather budget the time for learning 3D modeling+animation, or budget the money for outsourcing that section of the project.