Great idea to start with a visual novel. You're working alone and it's a lot you have to learn to create even the simplest of things. I also use AI for consulting on avaiable tools I can use when coding. I try to code everything on my own, but instead of consulting on documentation, which usually takes a while and I may miss something, AI will be spot on at what I need and I learn a lot from it. Still, sometimes AI fails hard, then I go to the documentation or ask online if it's really a dead end.
Your game is well written, you got a good grasp on dialog. It's an enjoyable chill out story, I'd say, with an interesting plot twist at the end. But the character shows the left shoulder when he was bit on the right, that could be worked around by flipping the image.
I liked that you implemented a main menu with options and a toggle for fullscreen. I didn't mess with the buttons at the bottom of the screen, but it seems they allowed for saving and loading and some more stuff, which is interesting for a first game.
All in all, you did great for a first entry, especially working solo. Just keep it up, it's a long road, but if we keep the pace we eventually get where we want to.