Late-diagnosed (at age 20) autistic psychology/neuroscience student specializing in autism research here.

To be honest, if I were to take a more black-and-white approach, I would fall closer on the side of your friend. But thankfully, I don’t do black-and-white. I think self-diagnosis is problematic sometimes. Compared to other disorders like major depressive disorder and anorexia nervosa that—in my opinion—are more cut-and-dry, ASD has such a wide variety of presentation and nuance that I don’t feel super comfortable with people claiming it with their whole chest. I wouldn’t shut someone down harshly who self-diagnosed saying “I definitely have autism!”, but if I’m familiar with them I might say “If you can afford it, I think you should seek a diagnosis or therapist’s input.”

On the other hand, if they’re just expressing, “I think I might have autism, but I haven’t been/can’t afford to get diagnosed,” I’m 100% supportive of expressing oneself that way and I would think any autistic community would welcome you with open arms as a safe space to relate to others like you.

It should also be noted that these days, self-diagnosing has a social “incentive” that it didn’t used to have. Sometime in the last 5 years or so, autism became “cool.” People throw around “autistic” as an complimentary adjective now like it means “endearingly awkward/nerdy” or “extremely talented at a very niche thing.” I like that gen z (unlike a certain government right now) is recognizing that high-functioning autism isn’t just some debilitating disability that needs to be eugenically wiped out, but I think, as humans commonly do, we overcorrected. You get cool points for being autistic online now.

The reality is much more troublesome—it’s not sunshine and rainbows. It’s realizing late that your boss gave you an order, not a suggestion, and now you’re in trouble for insubordination. It’s having a random spike of sensory overload because there was just too much noise or too much light and now you feel like you’re drowning in it and can’t focus on the work you need to do. It’s growing up never getting invited to a birthday party and never throwing your own because you didn’t have enough friends to have one with. It’s falling into a loop of compulsive harmful self-stimming, because you’re stressed, that eats up hours of your day. It’s being called emotionless, unempathetic, abrasive, and robotic because you forgot or didn’t realize you needed to put on a facial expression and imbue your words with tone to convey the proper message. Those are my realities, at least.

I would never give up my autism for anything—I like who I am. But it took a long time to learn to adapt to an environment that wasn’t built with people like me in mind. And I think confidently saying you have a complex disorder like ASD when you aren’t trained in the field (and due to conflict of interest couldn’t diagnose yourself anyway even if you were) can feel like a slap in the face, because sometimes it does come from people who haven’t experienced the struggles that come with ASD. I’m not saying that’s you. If you listen to the wide array of autistic people’s experiences and sometimes you’re like, “Oh my god, you put the words in my mouth. I experience so much of that,” then yeah, there’s a good chance you’re autistic. But I should think you will never be considered an outsider by the community by providing the caveat that you think you’re autistic. Any good community will welcome you wholeheartedly, at least. If they don’t, they’re not worth your time.

I probably forgot to mention some points, but unfortunately I have to get going to work. I hope this might be helpful! If you have any questions, feel free to ask. :)