SCHOOLING IN THE NETHERLANDS
If you come to live in the Netherlands with children, you must be aware of the Dutch school system and the rules about compulsory schooling. All children as from the age of 5 till 16 years are subject to compulsory schooling. This also applies to children of international students. Sometimes an exemption is possible. Children must attend a school at the latest from the first day of the new month after they turned 5. Most children attend school as of 4 years. But 4- year olds are not subject to compulsory schooling. Children younger than 4 years can participate in a playgroup or preschool. However, this is quite expensive.
You can find additional information here.