Welp....if you're going to college, or just living on their dime in general, you're pretty much screwed, as "living under dad & mom's house rules" is usually the condition that comes with those situations. However, if you're NOT going to college, you have a job, you have some money put away to get your own place, and you're not under any sort of parole or legal guardianship (due to mental/physical illness), they have NO legal right to force you to move away, against your will.
P.S. What's wrong with being a country girl? I grew up in the country, and actually prefer rural areas to the city-- and I'm a pretty happenin' chick!