Ask HN: Animation Software for Kids?

I'm not sure if your 4.5yo is old enough to try Scratch[1] but nothing is too young these days. My elder got into Scratch around that time. These days, my younger one is into https://code.org and she make things go around, do stuffs, etc.

1. https://scratch.mit.edu

You could try showing her some documentary going over how some particular professional animation was made in detail. It sounds like she doesn't just want to make her own kid version of animation, but rather wants to learn how professional animation is done.