I don't feel the need to be diagnosed for similar reasons as the OP. I'm 48. (I've been saying almost 50 so that 50 doesn't come as a shock in a couple of years.) I'm married and the mother of five. I've already figured out how to get through life with my brain, and now I have the information I need to find more tips and tricks.
My husband tells me that we should go to an accountant to get our taxes done because I hate doing them. But I tell him that that would be absurd because where does he think the accountant will get all of our financial information? From ME. So I'd still have to do most of the work, but I'd also be out of the money that he would charge.
I feel about the same way about being diagnosed. I can go spend a couple of thousand to have an expert opinion, but the expert will be looking at the information coming out of my own head. After a ton of reading and going through Cynthia Kim's
I Think I Might Be Autistic, I'm as sure as I can be already. I don't need to be convinced, and I don't think I'd believe an expert who told me that I'm not, and that has happened to people who were later diagnosed.
The only reason that I kind of want a diagnosis is for my family members. They have told me since I was little that they don't know where I came from, that I'm an airhead, that I'm all book smarts and no common sense, that I just go on and on and on about things; they call me grace because I have none. And I kid you not, my sister, just a few months ago, brought up a story about when I was learning to drive: "Ha ha, I heard that when you were learning to drive, you would pull over to the side of the road when another car was coming towards you." (I still slow down and scoot over as much as I can.) But when I said I was autistic, they didn't believe me.
But a diagnosis might not convince them either, so I've just decided that I don't give a rat's ass about what they think about this. If they want to know for certain, they can pay for the diagnosis.
I just don't think that it would get ME anything.
The KNOWING is different from the DIAGNOSIS, though.
Knowing is important.
Knowing is what helped me understand a thousand awkward, uncomfortable, weird, confusing events and conversations from my lifetime.
Knowing is what has helped my husband of almost 30 years to understand that I'm really not being deliberately perverse when I correct him when he has a detail wrong in a story, when I argue over semantics, or when I ask him to just freakin' park on row 6 at Walmart, for Pete's sake, because THAT'S WHERE I PARK AT WALMART, AND IF IT REALLY DOESN'T MATTER, THEN JUST PARK WHERE I WANT.
Ahem.
He has ADHD, and I have autism. Knowing these things helps us to understand each other better, though I still have trouble understanding why he can't just put his keys in the same place all the time and why we couldn't find his phone for three days because it wasn't charged when he lost it, and he can't understand why row 6 is important to me. But we at least understand now that there are legit reasons for both of those things and that neither of us is intentionally making the other one crazy at times. That's huge.
But I didn't get those things from a diagnosis; I got that from knowing. If you need a diagnosis to KNOW, then it's extremely important. And if you can know without that, then it may not be important to you at all.