If u want your b to be the youngest in class and possibly the slowest in learning, then u can cut in N1 class mid-term when b turns 2, and go to K1 in Sep 2008. Then apply NOW! some schools are full, only pm class available. My b will cut in in Feb 08 to N1 second term.
If u want his grades to be better, u can delay for 1 year and go to N1 Sept 2008. THen apply this Sept.
most kinders are 3 year (k1-k3), nursery is one more year (n1-n4, ie. n2=k1). But some kinder are only 2 years, like St. Joseph and some international schools.
min age for p.1 is 5 yr 8 months.
I will let my boy be small b. If he cannot keep up, we will let him repeat 1 year before p1.