The period of a probation order must not extend beyond the child's twenty-first birthday and must not exceed—
(a) if the child is under 15 years of age on the day of sentencing—
(i) 6 months; or
(ii) 12 months, if the circumstances are exceptional; or
(b) if the child is 15 years of age or over on the day of sentencing—
(i) 12 months; or
(ii) 18 months, if the circumstances are exceptional.
Division 4—Youth supervision and support orders