Is 16-17 a minor or adult?

When I was talking to my parents before they were telling me that when I was 17 if I didn’t like it here that I could of just moved out or left without telling anyone and nobody would of even question or report it. They also told me about how 16 year olds get married and that if a 17 year old went to the hospital the staff there wouldn’t need to check with the parents or notify them of anything. I was curious if it’s true because when I was 17 I thought by law that means I was a minor and legal age to move out or to do almost anything was 18.