Firstly, it's important to note that your parents care a lot about you and that's why they overprotect you. They cherish you so much and wouldn't want to let you get hurt, make wrong decision and so on.
You have to talk about it with them. Spell out your concerns. Let them know they are impeding your privacy or even choking you. All these must be stated in polite language anyways. Else, they may frown at you and feel like you're being rude.
This leads to another point which is patience. Try as much as possible to be patient enough to see them adjust gradually. The change cannot be instataneous rather gradually. Don't feel bad when you don't get to see changes as fast as you wish. Be patient.
Also, show your parents that you can stand on your own, think on your own,do things on your own etc. Show the traits of being independent. This could be in the way you dress maturely, speak confidently, carry out chores without being told and so on.
Above all, respect your parents. They are more experienced than you and they know what's good for you.
Thank you for your time .