(1) The provisions of this chapter apply to the following in the same way as they apply to young offenders and young detainees who are under 18 years old:
(a) an adult who is under 21 years old (a young adult ) being dealt with by a police officer or held in police custody in relation to a youth offence;
(b) young adults being dealt with under the criminal law system for a youth offence;
(c) young offenders and young detainees who are adults.
(2) In this section:
"youth offence", in relation to a young adult, means an offence committed or allegedly committed by the young adult when under 18 years old.