You’re 19 years old. You have social anxiety, you’ve been deprived of schooling and the social experience of school. I’m so very sorry that this has happened to you.
If your parents have a car, ask them to help you to get a driver’s license. In many parts of the country, this is a first step towards independence, being able to get to school and work. You need to get a job, ANY job, even if it’s the lowest level employment at a place you can walk or bike to. Having a job will help to start to build the ability to tolerate social interaction that you would have learned naturally, had you attended school, over the past 12 years.
Are you parents willing to help you with community college? You can start at the very beginning with math there - they will have the right classes for you. If your parents don’t have much money, and are willing to file a FAFSA, you’ll be eligible for Pell grants, which will help greatly with community college tuition. For all the reasons outlined beforehand, community college is where you need to start. You’re not ready for a 4 yr college, neither academically nor socially. You need to live at home and start at community college. If your parents are unwilling to do anything to help you, go to the community college fin aid office and state your case. Tell them the truth, that your right to a free education was taken from you, and that you need help. I think that they will help you.