Yeah. I hadn't clocked the 7-y-o part, I agree with Bozza, that would be problematic.
I really don't hold with the idea that Tokyo is more hectic than NYC though - there are lots of people but it's a lot calmer. You don't get people shouting at you if you take longer than a nano-second in...
You should definitely go, it's a fantastic place to visit. It's a busy city but it's nowhere near in your face as NYC is. Public transport is really efficient and straight forward to use and there are plenty of excellent places to eat. It's a definite experience. I had less than a week there...