There is no point in trying to keep Prince George's entry to nursery school and the name of the school quiet because it would be found out very quickly and the paparazzi would be hiding in bushes with their telephoto lens to photograph him.
His parents have an agreement with the reputable British press for them to respect the privacy of their children and not buy paparazzi photographs in return for receiving reasonable information about the children and progress photos. The photographs just released, taken by the Duchess of Cambridge, shows just how well the system works. The Prince started nursery just like other children with only his proud parents to photograph him.