I had a similar experience.

• Most of my friends were generally similar: straight-shooters, into science, and unique.
• I had a friend whose kid I related to so much, that eventho I am generally pretty bad with kids, they used to ask me for advice on how to address certain issues with him.
• When I was at a farmer's market, I saw some toys that looked interesting. I asked the salesperson what they were for, and she responded saying that they were for autistic kids because it helps them calm down. I seriously said, "Man, those autistic kids know what's up." I bought two of the toys. One was for the kid mentioned above, and the other was for me.

A year later, a friend that is a psychologist tells me that I'm autistic. I get a formal evaluation just to make sure, and yep, I'm certainly autistic. For the next year, all these odd experiences in my life start to make sense:

• I tell my friends and they said that they are autistic too and thought I knew because it was so obvious.
• I learn that flappy hands is an autism thing. The kid mentioned flapped his hands whenever he would get excited. They weren't necessarily asking me how to raise their kid. They were asking me for advice with autistic traits and issues.
• They toy was a fidget toy, and I bought one for myself because it was soothing... because I am autistic and adhd.