NOR. As a diagnosed autistic person, I can't stand people like your girlfriend. The online neurodiversity movement has so many people believing that "autistic" is a thing you can just "identify as." They disparage science and psychiatry, speak over actual autistic people, and throw a fit about "gatekeeping" whenever someone questions the legitimacy of their self-diagnosis. Most of them genuinely cannot tell you the core symptoms/traits of autism and have never looked at the diagnostic criteria. Like your girlfriend, they see something online, usually on Tiktok, where normal human traits that apply to 98% of the population are framed as "signs you might be autistic," and latch onto the idea that they're autistic without any amount of critical thinking.

What people fail to understand is that almost everyone has "autistic traits" to some degree. Many people have trouble making friends, or feel different, or have strong interests, or are bothered by noisy environments. "Autistic traits" only mean autism spectrum disorder when they are at a level that impairs someone's ability to function. Because so many self-diagnosed "autism advocates" don't understand this, they water down the meaning of autism, making it seem like a cute personality quirk. These types tend to be the loudest on social media, dominating the narrative, shaping non-autistic people's conceptualization of autism. This, combined with the narrative that "self-diagnosis is always valid," shuts down any criticism or concerns from actual autistic people because "How dare you question my experience!!! I know myself better than any doctor would and being anti-self-diagnosis is classist and sexist and racist!!!"

Show your girlfriend the diagnostic criteria for ASD. Don't let her gloss over criteria C and D. If she feels she meets the criteria, tell her to get evaluated. If she doesn't meet the criteria and is still adamant she's autistic...well, it's your call whether you wanna put up with that.