(1) A child witness , in relation to a child proceeding:
(a) is a child (including a child complainant) who is a witness in the proceeding; and
(b) includes a witness in the proceeding who was a child at the time the offence concerned was alleged to have been committed.
(2) However, a person who is 18 or over is not a child witness if the person informs the court that the person does not wish to be treated as such a witness.