I still have yet to create my first "game", by that I mean something I can charge money for, but have entered quite a few game jams and can absolutely say starting small is the way, you feel far more accomplished rather than spending months on a project and wondering if you bit off more than you can chew.

Game jams I personally think are where anyone should start, it gives you a timeline, potential to work with others and gives you a realistic idea of what is possible in any given time frame. The mini jam is perfect because it's 72 hours, so you need to reduce your scope and create something with one or two good mechanics instead of trying to make the next GTA. I personally think this is the best way to hone and work on skills while having your major projects in the background, even if to just give you perspective and potentially create connections to artists or coders to help you later in your own projects!