You can always go back and refine that art into something better, and as you progress your skills WILL get better. As you build your game with this first-draft artwork, you'll get a better picture of where the game is heading. You may think it's ugly, but it's something. I suggest moving forward with your 'first draft' artwork. Suppress your imposter syndrome, and keep moving forward. People can praise the art and exclaim how great it is, but you probably won't believe them, or you'll think they're just trying to be nice. No matter how skilled you get, you will most likely never be 100% satisfied with your artwork.
Keep in mind, as an artist, you are your own worst critic. Make the thing with the skills you have now, and improvement in the art will come naturally through doing, and the more you make, the better it gets.
If you worry about making your art perfect, you'll end up like me, just spinning your wheels in one place for years or decades and never actually making anything.
