J.B.
If she has an IEP at school, they should have had a transition plan for her when she turned 18. Vocational Rehabilitation and services to help her become independent, maybe even a group home to live in. I would ask the folks at her school about that. Is the reason she demands things due to her disability? Can she distinguish between needs and wants? If she is 18, you may need to have papers drawn up for guardianship, or else she can get herself into all kinds of financial and legal problems, and you have no power to stop her since she is 18.