Hey there. I just went through the coming-out process to most of my friends. And it feels like a huge weight is off my chest.
There are a few routes to talking about it - when someone makes a comment on 'why did you just do that', when someone talks about autism or autistic children, when someone talks about having bipolar or whatnot. I like to say, well, as a person with autism, I - like just kinda slip it in there.
That way they sorta do a double take while midstream, or they're more casual about that. Be ready to answer questions and hold their hand through learning about this stuff. Be strong, have confidence when u do it. Actually, confidence will build when you work your way up to it.
We need folks to be out of the closet about this stuff so that we can raise awareness. Kudos to you.