Well, the law has mixed views on this.....
At 17, the police will treat you as an adult. There is a campaign to have this changed to 18.
You can drive at 17, but you can't vote.
You can get married.
You will pay N.I if working.
You can sometimes accompany under 16s to events/on planes etc as an adult, but not always.
You surely don't have much experience of life at the age of 17 though.
I think of 16-17 as being older teenagers, like some of the older teenagers. I think brain development is becoming less chaotic teenager and more adult usually at about 17.