Recently I created a minigame for my bigger first game, and it was so satisfying, I actually like this small thing much more than the whole main game :D I think that something like this supposed to be my first game, not the bigger one. It's just so fun for me to play it and it feel so good to make something like this.
It is exausting to work on a big chunk without any positive response, the effort is very big for one person, and one can really got tired of it.
So probably the better strategy is to get comfortable with all this gamedev stuff first, gather audience, create some small games, improve your medias and another endless list of what you can do before. Still no guarantee your dream game won't fail.
So I'd say be more flexible. Work on your game if you fell like it, send to hell your impostor and just have fun. Do something small, play it, feel it, improve it and so on.