I had to present my psychiatrist with a truckload of academic research which I had done before he understood AS enough to concur with my self-diagnosis. And it wasn't as if I was lobbying him for it, rather I was truly trying to understand why I seemed to see and think differently than the "average" person. I had persuaded myself that it wasn't simply a high IQ, that there was something else.
It appears to me, from my limited time studying it and reading posts from people who have it, that the real experts on AS are the Aspies themselves. We're introspective, curious and logical by nature, and tend to analyze (and even over analyze) things to death. So it's perfectly logical that in our quest to understand things we will at times turn our attentions inward. So, I'd say that an official diagnosis may provide validation and even a sense of relief, it isn't strictly necessary.
Bottom line, if you see enough of yourself in the posts you read here, whether or not you fit some textbook definition (probably written by someone who doesn't really understand AS anyway), it's likely that you will find value here, and a better understanding of yourself. It's certainly been true for me.
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Scientia est Potentia