For example, some K1 accept kids from 2006Sep to 2007 Dec, some accept 2007Jan to 2007 Dec, and like Pui Ching, their cut of is the kid need to be 3 years old in Sep 1. That really depends on which school you are choosing.
My suggestion is that if there is any pre-N accept your kid, why not just study first and later repeat in K1 or pre-N.