(1) Where it appears to a competent authority that person brought before it under any of the provisions of this Act (otherwise than for the purpose of giving evidence) is a juvenile or the child, the competent authority shall make due inquiry so as to the age of that person and for that purpose shall take such evidence as may be necessary (but not an affidavit) and shall record a finding whether the person is a juvenile or the child or not, stating his age as nearly as may be.
(2) No order of a competent authority shall be deemed to have become invalid merely by any subsequent proof that the person in respect of whom the order has been made is not a juvenile or the child, and the age recorded by the competent authority to be the age of person so brought before it, shall for the purpose of this Act, be deemed to be the true age of that person.