+1 on this. Even as an adult I found other game authoring systems too complex to jump into and feel comfortable with (as a hobbyist). Pico-8 was the fastest, easiest "I'm thinking of something" to "I'm seeing something happen on screen" iterative development cycle and a joy to use. Plus, a great community of people willing to help on lexaloffle.com and especially Discord. Some great YouTube tutorials out there as well.

I learned to code games in QuickBASIC, and pico 8 to me is the closest experience I ever had to that. The tools for putting something on the screen are immediately available with no infrastructure work required. You don't need to create a window, load files, choose a screen mode or anything. You just draw a sprite in the sprite editor and call `spr`

Yes, it's very accessible. My son wrote a game on it (with a lot of help from me, but he got it).

+1 to this, my son really enjoys programming for pico-8