Preschool is an educational option for parents in Canada that is not mandatory and is for children who are too young to attend junior-kindergarten or kindergarten school programs.These programs, run by school boards across Canada in most provinces and territories, usually start at age four or five, depending on the province you live in. Also referred to as nursery school, early childhood education, day-care and childcare, preschool, preschool starts for most children who are entered into the program at two-and-a-half years old. Depending on the school's policy your son or daughter may have to be toilet-trained to attend, but isn't always a requirement so be sure to inquire. The government does not usually fund preschool, so often parents must choose a private preschool option.