My eldest was already doing amazing things with his arduino when he was 7, well before his reading and writing skills caught up. I deliberately held back with help on certain things to force him to RTFM. His fierce desire to figure it out did wonders for motivation.

It is gratifying to hear an 8 year old correctly use "instantiate" in conversation. We did have to warn him about using "magic" words amongst his "muggle" friends.