I think everybody has a stage like that, even myself, although in my case by the time I realised I had autism I'd already had to deal with that because of being mostly homebound with ME/CFS. Also, I think perhaps I have a different perspective of autism based on my upbringing. I had an intellectually disabled uncle and a grandfather who was an amputee (he had lost the fingers and thumb on his left hand), so I don't have the stigma associated with being perceived to be not normal, because for me not normal was somewhat normal. Also, by this point I was well aware of well-known people who had been diagnosed, and my nephew has the diagnosis of ASD.
Add that to the fact that I've always felt inherently like I didn't fit, no matter whether it was among family, close friends, etc. I think that may have been my subconscious realising that no matter how well I mask, it's not a natural social environment for me.
On a complete tangent: I read about something called the double empathy problem and I genuinely think some of the difficulties we face interacting with neurotypical people are the result of it (sorry, too much typing to explain, better for my ME/CFS if you look it up)