Thanks for this info CB. This is just the thing I was looking for and it's all very helpful to get the 12yo started without stressing out too much that he'll let the magic smoke out.
The other thing that's very appealing with this is the (this) community and open source not to mention the cost. 99.9% of the post are very encouraging with all the people out there willing to provide valuable input into designs and code reviews.
I'm hoping my son will find this interesting and challenging and that he'll also be keen to share his progress with you all.