adult child disability

I have been receiving SSI for the past 20 years and unable to work. 6 years ago it was discovered that much of this was due to a genetic disorder, Ehlers Danlos syndrome which I was born with. Although I worked prior to receiving disability, I never did achieve SGA due to ongoing physical problems which are now known to be due to the EDS. I think that I am technically eligible for adult child benefits, but the severity of my condition prior to age 22 would be hard to prove. I have been hesitant to pursue this now. Do you think it is worth taking to an attorney, or who would I consult for this?
Julie