Can they make decisions regarding medical treatment, insisting on a blood transfusion against parents wishes, for example? Or refusing aggressive cancer treatment and opting for palliative care instead? I'm not disagreeing with you. I just want to get a sense of the law in the US.
The current controversy in the UK concerns Scotland, which has reduced the age at which a person can unilaterally decide on transgender issues, from 18 to 16. A decision which has been blocked by the UK parliament and will be decided in the courts.