A Bill which has just been passed by Parliament allows schools to enrol children before their fifth birthday.
The new rule means that children can start school from the beginning of the term closest to their fifth birthday.
Until now their fifth birthday determined when they would start school, and Education Minister Nikki Kaye says the system needs to be flexible.
The Bill also contains other changes to the education system, and Ms Kaye said it was the most significant update for 30 years.
It makes clear that seclusion – isolating misbehaving children – isn’t allowed.