You've maybe (probably?) heard of it but Scratch (https://scratch.mit.edu https://scratch.mit.edu) is a good "code-like" system for when kids are really young.

You've maybe (probably?) heard of it but Scratch (https://scratch.mit.edu https://scratch.mit.edu) is a good "code-like" system for when kids are really young. You still have a way to go from 4 months of course, but I imagine it might be a bit easier to gain traction with something graphical (and colorful, and animated, etc.) than with what amounts to text editing.