So we are hearing about lot of 6-8 year old writing code. I'm trying to figure out what is normal and what are edge cases. I'm wondering... What is the age the

So we are hearing about lot of 6-8 year old writing code. I'm trying to figure out what is normal and what are edge cases. I'm wondering... What is the age they start reading proficiently? What is the age they start writing effortlessly? What is the edge they can read a web manual for, say, Racket and actually understand it?