Ariz. Rev. Stat. § 15-821 – Admission of children; required age

A. Unless otherwise provided by article 1.1 of this chapter or by any other law, all schools shall admit children who are between the ages of six and twenty-one years, who reside in the school district and who meet the requirements for enrollment in one of the grades or programs offered in the school. A school may refuse to admit a child who has graduated from a high school with a recognized diploma.
B. If a preschool program for children with disabilities is maintained, a child is eligible for admission as prescribed in section 15-771.
C. If a kindergarten program is maintained, a child is eligible for admission to kindergarten if the child is five years of age. A child is deemed five years of age if the child reaches the age of five before September 1 of the current school year. A child is eligible for admission to first grade if the child is six years of age. A child is deemed six years of age if the child reaches the age of six before September 1 of the current school year. The governing board may admit children who have not reached the required age as prescribed by this subsection if it is determined to be in the best interest of the children. For children entering the first grade, such determination shall be based upon one or more consultations with the parent, parents, guardian or guardians, the children, the teacher and the school principal. Such children must reach the required age of five for kindergarten and six for first grade by January 1 of the current school year.
D. Notwithstanding any other law, a child who resides with a family member other than the child's parent while awaiting the outcome of a legal guardianship or custody proceeding is deemed to reside in the school district where that family member resides if the family member provides written documentary proof of one of the following:
1. 1. The family member is attempting to obtain legal guardianship of the child in an unresolved and uncontested guardianship proceeding commenced in superior court. The family member shall provide documentation to the school district within thirty days of enrollment that the family member is attempting to obtain legal guardianship of the child. On obtaining legal guardianship, the family member shall provide documentation to the school district.
2. 2. The family member is attempting to obtain custody of the child in an unresolved and uncontested child custody proceeding commenced in superior court. The family member shall provide documentation to the school district within thirty days of enrollment that the family member is attempting to obtain custody of the child. On obtaining custody, the family member shall provide documentation to the school district.