First familiarized myself with the term last year, while being diagnosed. Was seeing a psychologist for depression, who had requested to review my history. That's when we found a psych evaluation from when I was 6(1995), that said that I seemed to meet the criteria for PDD/NOS, but nothing was ever done about it, diagnostic wise. I guess because I was already getting extra help in the special education program at school, and had been diagnosed with severe ADHD at age 4, it was just overlooked. She(the psych) thought I could have some sort of PDD/ASD and wanted to refer me to someone else, which I at first refused because I couldn't believe I had some kind of autism and I found the idea horrifying. Back then, the only kind of autism I knew about, was from kids I had known in school who had a more classical autism. Hell, I had a boy in my class in 5th-6th grade whom I am quite sure now had some kind of LFA though I did not realize at the time.
I started doing my own research after that, reading about it, learning about it, but it wasn't until I saw a show on tv called Autism x6, that I really started understanding what it really was and could make more sense of what I read. Ultimately, I decided there may be something to it, and as much as I didn't like the idea, I nervously decided to see this other specialist because I was now curious. I ended up getting diagnosed with AS, which did surprise me, as I thought it would have been PDD/NOS if anything like it was noted in my youth, but the diagnosis had only reached the DSM IV when I was 6. I now know that my ADHD was/is just secondary.