I got my 8 year old an arduino, so I'm secretly taking him through Kernighan and Ritchie. Each night I teach him a new little snippet and the next day he'll run with it. Its fascinating to watch as he takes the concept and pushes it as far as it will possibly go, ending in a massive barely working kludge... and then the next night we learn a few new lines that make it all simple and easy and its sheer joy. Its like watching Peter Parker get spider powers.

Just learning that programs could be broken into callable functions was a moment of stand up, open mouthed wonder.

Don't wait. Do this with your kids now.