Nice work! This is a perfectly respectable little match-3 game, and really good for a first attempt. I can only imagine the number of things you picked up along the way, mouse interaction, animation, sounds and looping, web builds for Itch, etc. etc.
It seems redundant to give you constructive feedback since I'm sure you already have a long list of things you want to learn, but as an example: the sound loop has a noticeable start/finish. If you made it quite a bit longer, I think it wouldn't be so noticeable?
I found the controls a tiny bit opaque in that there was no drag animation... the block only moved after you release the button. Adding a drag animation would make this feel quite a bit more dynamic, and help the new players understand what was going on.
Congratulations on submitting, that's a really big deal and best of luck with your work.