These are clubs for parents with children of the same age
Do you mean in terms of affiliation to primary schools, or preparedness for primary 1? For the first, the only affiliated kindergartens are the MOE Kindergartens (can apply in 2A2 to the primary school that the MK is in). For the second, I'm not sure, though I imagine most kindergartens/childcare centres will bring kids up to the minimum standard needed for P1 at least? (Not sure what that is - reading, writing, counting, simple addition?)
My child is in P3 this year. Looking back, I think I’m glad that he attended a kindergarten that had 27 kids in each K2 class. In his primary school, they have 30 kids in each P1 class, 40 kids in each P3+ class.
Unless your child is going to be attending a less popular Primary school (ie those which still have plenteous vacancies after 2CS), better to get the child used to big classes and less individual attention, as early as possible.
There were several classmates from very small kindergartens, who had a tough time transitioning into P1. Maybe introverts also have a harder time dealing with a big rowdy school environment in P1. Imagine the school grounds teeming with P1-P6 kids and teachers before assembly & after school. It’s like a fish market...a P1 child will feel lost in the crowd of faces too, need to get used to independently getting around the campus without any parent by his side also.
The P1 kids need to do Show & Tell, so hopefully your kindergarten has been training the K2 kids to do this. Speaking & making a presentation in front of an audience. Also they will be graded on collaborative behaviors instead of academics. So your child needs to be capable of getting along with other team members, resolving disagreements amicably etc.
P1 will have Spelling & tingxie, albeit ungraded. I believe MOE Kindergartens do NOT have Spelling & tingxie, but it is something that all primary schools still do. So the kids who are familiar with the home routine of practising for weekly Spelling & tingxie, will have an advantage. Start training them at home on THE ROUTINE (not so much of the level of difficulty of words themselves) from K2 age if they don’t already know. Plenty of parents (and kids!) have cried tears of frustration when the preschoolers just don’t grasp the concept of sitting down to practise. If they don’t have a dedicated study time, they won’t be able to handle doing P1 homework responsibly.