Jason,

I dont think 6 years old is too young: one of my flying friends here started when he was 6, and soloed before he was 7, when his dad just walked away and told him to fly it and land it !!! He is now over 40, and needless to say that he is an excellent pilot.

However, be prepared for the kid shifting his attention to new areas of interest at any time: I tought my son to fly when he was 14, and he lost interest soon after his first solo flight; he got into RC cars for a few months, but now 16, he is completely out of RC.

I dreamed about RC flying when I was 14, finally could afford it when I was 20, and have now been flying for 28 years.

Good luck, and have fun.