My DD (about to be 17 going on 27, thinks she knows it all "I'm practically an adult!"). She's a very strong person who knows her own mind and is very, very focussed on her own agenda.
We have frequently locked antlers over what she does. These arguments are loud, explosive and leave me shaken/ furious/ at my wits end/ miserable... You know how it is.
Recently, however, I have developed a new strategy. Instead of saying "No, you are not doing x". I have started saying "You are old enough and sensible enough to make your own decision regarding x but my strongest recommendation is that you don't do it because of y".
In my mind I am saying "Don't do x". She hears "You're grown up and mature, you're sensible, I trust you to make your own decisions regarding your own life". So far she is falling in with my "recommendations", we're getting on really well and we are not having any of these awful arguments.
Sometimes, with teenagers, I guess it's not what you say, it's the way that you say it?
Just thought I'd share what currently seems to be working in our house
Cyril