that really sucks. sorry it didn't turn out in a way that matches your lived experience.
are you by chance also high IQ or INFJ?
i read and heard in autism podcasts that people with certain above average perception sometimes begun masking so well and from such an early age that it seems to others (and sometimes to themselves) that the mask is part is their core nature, as opposed to simply second nature. this is part of the effects of 2E ("twice exceptionality"; the name is problematic, try not to fixate on it)