Well, in all honesty that may be a hopeless proposition. Hard to tell if or what it might take to get them to see and treat you as a peer instead of a dependent. That so many parents can act in an overprotective manner of their children, adults or not. Autistic or not as well.
It's a consideration that makes a number of us here openly in doubt about organizations like "Autism Speaks". Which functions as an advocacy organization representing not autistic children, but rather the interests of neurotypical parents of autistic children. Another consideration in how some parents are enabled to treat their own kids as something less than they are.
But what really counts is what I think you've demonstrated here. That you can and will stand up for yourself. That YOU think about who and what you are counts the most.
That sometimes the only real alternative to our issues to seek out help from our own who best understand and can relate to the plight of being autistic in a neurotypical world. When more often than not we must prove we are more than so many may assume.