I admitd my son to nursery in June... i.e when he was 2.6 yrs... so he will be 3.6 yrs when he'll move to L.K.G... and at the age of 5.6 yrs he'll be in 1st standard... I just wanted to know what is the right age to join for first standard?

Can you tell us what nation and what educational system this is.
Obviously it is not the US or Canada.