Only a child placement agency may petition for guardianship under this subtitle. A court may grant guardianship under this subtitle only for a minor. A petitioner shall attach to a petition: all written consents for the guardianship that the petitioner has; and if applicable: proof of guardianship or relinquishment of parental rights granted by an administrative, executive, or judicial body of a state or other jurisdiction; and certification that the guardianship or relinquishment was granted in compliance with the jurisdiction’s laws.