Early Childhood Screening Minnesota State Law requires that all preschoolers be screened once prior to entering public and some private kindergartens. School District 761 begins inviting children to screening at age three. Earlier is better! Waiting until a child is ready to start school may be waiting too long. It is best if your child can be screened when they are 3 years old, or at least a year before entering kindergarten. Early Childhood Screening is FREE, but families still need to "check out" to be registered.