I also vote for the "make a plan to leave at some point". A plan doesn't mean you start looking for places. It might be a plan that gets you out in a year or so, but this way you'd have a timeline, steps to take, etc.
I understand sneaking out might be a problem, but if your mother disapproves it will be even worse after you tell her, as she'll watch you even more. She seems very controlling, and as mine was like that too, I'd be very careful about it. It's hard to get any freedom with a controlling parent, even after I moved out my mom would come into my apartment when I wasn't there and check my drawers and stuff (my parents had spare keys in case I got locked out or something).
Even if they wouldn't kick you out, the relationship might become really strained, and that could resonate in all other areas of your life as well.
In the end, are you studying from home or in college? It sounds to me like you mom wanted you to study from home so she can keep an eye on you/ keep you under her control. Going to college is at least one way to "escape" and have a bit of freedom. You can try little by little and she if she tried to be more and more controlling or lets you go.
In my case I had to move to another continent before she left me alone, but I would say she was an extreme case.
If you make a long-term plan to move out, then you can start thinking of things like income (how much would you make? How many months would you work and save up prior to moving?), and expenses such as rent (how much is rent in your area? Could you reduce it by having a roommate or roommates?) and transportation (if you can't afford a car at all, as there other options? Public transit? Carpooling? Shared car services?).
You might actually test the waters by first talking to your parents about the option of moving out, and see how they react. Maybe they'll try and support you, although controlling parents tend to want their kids to stay forever.
I assume you wouldn't want to come out partially? That is, introduce one of your partners and not the other? I can see how it would be unfair to the other, but it could also be a step, rather than introducing both at once. I have no idea how much it might or might not help, but I thought I'd throw it out there.
EDIT: Duh! You're still in high school, not college yet! I should have paid more attention. Well I hope you won't go with the distance classes. Being away for school would give you a little bit of breathing room, even though you'll be busy studying.
Last edited by Tonberry; 10-13-2010 at 08:24 PM.