@deadgirl I suggest you think about an exit plan in case you are taken out of your home abruptly by authorities due to abuse.
Having a copy of your birth certificate, social security number, vaccination records, and contact info for trusted friends/family would be helpful. Do not ask your parents for these documents, but see if you can find them and make copies.
Do you have a drivers license, permit, or state issued identification? If not, that might be a helpful step towards independence.
Do you attend school where you know and trust your Guidance Counselor? Some GC are very knowledgeable and keep current with college admissions info. Other GC are overwhelmed with hundreds of seniors to process transcripts and recommendation letters for, and won’t have time, energy, or most accurate info to help you. It would help you (and posters here) to figure out if your GC is going to be an asset in your college journey.
Do you attend church? If so, Are there any trusted adults there you can confide in? Be careful, though, if your church is very legalistic and assumes the Father is always right, you could bring shame to your family by admitting how bad your home life is and be further punished.
Are you part of a culture or ethic background that has overriding traditions that are part of why your parents are holding you back? You mention a brother who is in private school? Are you a female and is that part of the reason your parents are not providing the same level of education for you?
Do you have younger siblings? Are they being mistreated as well?
You have a lot on your shoulders, and this is a great place to vent and get a better perspective of how your situation is not normal. You seem to be holding up your academics, and are seeing a therapist. I am kind of surprised your parents allow that, and shocked your therapist has not contacted police as required by law.
Keep posting and interacting here. This is a safe place.