It sounds like you are using a legal framework from medical treatment of minors. If I have that right, then you should know that there is an exception for emancipated people under 18 years of age.

Would you support the same exception for work, now that you know this or perhaps you would also eliminate this exception for them to control their own bodies in a medical context?

www.ncbi.nlm.nih.gov/pmc/articles/PMC4008301/#:~:….

Court-ordered emancipation. A child under the age of 18 who lives independently without the support of parents and makes his or her own day-to-day decisions may petition the court for emancipation. If granted, the minor will have the same legal rights as an adult, including the right to consent to (and refuse) medical treatment.