I agree 100% with @BigRedV on this one. I am an Early Childhood trained prep teacher. Kids are just so much more ready for school at 5-6 than at 4-5. It's not 'holding them back', school is compulsory in Aus from age 6. So starting them when they are 5 turning 6 should be perfectly acceptable for "society". Speak to any teacher, & they will always tell you that little bit older is better for the child. Why make them struggle when they don't need to? A prep class should be able to expect children to engage in classroom activities. There is nothing more frustrating than trying to teach 4 year olds who are too young to learn reading, writing, sitting at a desk, or holding a pencil. They should be outside playing in the sandpit at 4.