I think you should gain their thrust and respect.
Ooh, this sound stupid, yes?
But you just have to show them that you are mature enough to take more care of yourself than before and you must to be someone they can thrust!
I mean by this when you finally get your permission to do something they have never allowed you to do, do it as you promised without slipping any way ie. if you have promised to come home 12.00 pm. then be sure to come home then. This is how they build more thrust on you and you may even do it again.
This progress when they realise that you are not a child anymore can take long but it's good to proceed with some little things first.
Helping at home, doing your homework at time, giving the earned respect to your parents...
It's usually about thrust and both way respect here.
Okay, sometimes parents can be really blind.
Then it's time to stand up a little for them.
(I don't mean normal teenage rebellion here.)
Try to act mature and talk to them seriously and try to give them the idea about your point of view...
This isn't a unknown issue to me either.
My mother has always been overly worrying about me. (since her personality and the fact I'm her only child)
And this thing pissed me really off.
But I slowly gained her thrust and made clear that I don't do anything stupid and showed her that I'm mature enough to control myself.
Nowadays I'm 17 and I live alone in my apartmet in another city than they live.