Our local group, had an adult group set up already.
From my reading, and guesswork, I would think if you contact a local Autism or Asperger group, or a main group in your state, say in a big city
(sorry I only have basic knowledge of US geography),
just start contacting people by email if that's all you feel able to do,
and they may know of other adults or adult groups more local to you,
and can put you in touch with them!
Where I am we have a local group, of which to my last knowledge 100 adults are members.
Some are just silent financial members.
A few attended a social group, a different group attends the local seminars,
and another group who are no longer members but met through the local forum,
started meeting up.
You don't have to have a group to meet people, you might just find one other person, initially.