I have a four year old who is currently using the program. We actually started when he was 3 1/2 (so we have been using it about 7/8 months). I just put that he was five since there was no other option. I am not sure if this will be an issue later, but I will deal with it then. He is almost done with the first grade level. We are not on a regular schedule; it is just an extra "fun" activity for him.
I would say that the biggest issue I have noticed with starting so young is that it requires a lot of my supervision. He is very independent on the computer with normal games, but since correct/incorrect answers are being tracked I have to keep an eye on him to make sure that he is following the directions. We have had some issues with him pushing enter too fast (before filling in the complete answer) and other minor things, but in general it has worked well. It has actually been better since our setting was adjusted the gifted level. DS would become very frustrated when he had to answer so many of one type of question.
