I think you’d be cutting out a significant portion of the workforce by excluding those in early adulthood.
I’m guessing their position is very much “oh they still need to work and pay taxes…and they shouldn’t expect any more support than they currently have in order to do so…but they need to figure out how to manage it all without driving, and they should be disenfranchised as well”.
Almost the same age as you and I’m fairly confident I’m undiagnosed and have been since about 3rd grade as well.
My mom had such a diagnosis suggested to her multiple times but felt the stigma of a diagnosis and a medication to treat it was worse than just doing nothing. In her mind, I’d get diagnosed, given a label that would prevent me from ever getting a job or having a normal life, and drugs I’d take for the rest of my life that would make me act like I’d received a lobotomy.