I don't care what you say, the convience and "price" of living with them and having them provide for you is that you repsect their opinion.
Regardless of what any teenager thinks, a parent is not trying to ruin them, but simply looking out for them.
You seem like the kind of person who is rash, rushes to conclusions, stubborn and is a general pain in the ass. You should be happy your parents don't see the side of you that you are showing us.
Oh, and don't tell me that you can make it on your own being 18. That's just not true. If you REALLY want to live in a hole-in-the-wall apartment in the shhite side of town just so you can be a part of a sleep-over, try it.
Just because you pay some of your bills doesn't mean you can live on your own. Do you pay your parents for your portion of the insurance, or do you have your own? If you aren't on your own, once you don't live with your parents, you would be required to. Do you have your own car? A phone bill is the LEAST of your worries each month. Electric, Water... Gas maybe..? To top that off, you'd have a rent payment to make each month. What about medical insurance? I seriously doubt that any 18 year old has solid medical coverage without their parent's help.
Do you have any money saved up now? Even if you could manage to squeek by with the bills every month, what happens if you need to come up with some cash for things like car repairs?
Keep in mind that most people who move away from home early in life don't have the funds to pursue their dreams. You will be stuck in dead-end jobs that never really satisfy you, and you will have a harder time taking steps up. Once you leave your parents, you are officially in debt, if you haven't been before.
Be thankful your parents are giving you the PRIVLEDGE of providing for you.
Just don't squander the welfare money that I worked for when you end up in the gutter.