I think you picked a reasonable mechanic for your first Godot project. One has to start somewhere, and you started pretty well.
The art obviously is the strongest part in your game. And I like how you managed to design the transitions between the different game states. This is all smooth and well thought out. If I would optimize something in that realm, I would give each interactive element a micro hover + click effect (in ideal visual and audio feedback). Otherwise the buttons and options feel kind of dead and unresponsive.
Curious how your game dev journey continues. Combining game dev with art skills is a pretty strong combo, wish you best luck and lots of fun on that journey.