It really depends on the kindergarten you want your child to go to.
1) If you are in zone for ESF then you don't have to apply until October the year they turn 2. They will then start if they get a place in August the year they turn 3. So it doesn't matter if their birthday is Jan or Dec they will start in August the year they turn 3.
2) For International Schools I think they all have their own administration procedures so you would need to contact the school and ask when you need to register. Also some of the very popular schools have children that have been registered since birth so by the sounds it, it is never too early to apply for these schools.