What is your 4 year old like?
Does he dress himself, clean himself properly, understands a lot of vocabulary, good with numbers, knows letters and reads?
DS is 4 and 2 months, he still doesn't know the basic colours, counts up to 20, doesn't know clock, getting their with the days of the week, can write his name. That's about it. I have read some 4 year olds can count up to 100 and backwards and knows the numbers by looking at them and a lot more!