I would say submit a FAFSA and get a federal student loan and/or grant and go to college. I don't know all that much about the cosmetology field but they have to have something that benefits that field in university. If you need housing taken care of, grants and loans can cover student housing as well.

If you are at least able to pay your living expenses and have no use for full fledged college education then hit up a trade school which would also be able to be funded with a FAFSA and would also cost less than a 4 year university should you have to take a loan over a grant.

While I would advise against it, if you are still considering SSI, do what seesaw suggested and call the office and verify if you can work while the application process goes through. While I am pretty certain you can't considering the whole point of getting on SSI in the first place is to prove that you are too disabled to work, it could always be different in your state. If they say no, then you will have to decide for yourself if you would be able to wait several months up to a few years for your application to complete. If you would be unable to get your basic needs met yourself for that length of time and you can't have family help you, then going to college might be a better bet.