Hi, I suggest contacting your local KG1 school to find out the age requirements for enrollment.
In searching online to learn more about what KG1 is (we don't have a grade called KG1 in the United States), I found a KG1 teacher's website and it appears to be preschool age children. http://sites.google.com/site/missyosraskg1/
Thus, I'm including information about preschool below that you may find helpful. Thanks for asking!