There is a lot of cross-over between the two. AuDHD.

This is going to sound absolutely awful. Personal opinion, but I think ADHD feels like a great diagnosis to explain why you feel like you've spent a majority of your life "fucking up" as compared to others. Autism is a great diagnosis to explain why you have always been "weird" and "just can't be normal." As so much of life has taught us that if we can't just fit the box expected of us (which differs via gender, race, and socioeconomic status) we're broken individuals with little merit. I think a perfect example of this could even be seen in you having to be in your 40s before you actually might be able to setup some support systems for things you've needed your entire life.

Meh.

But also you know, nothing is perfect. Neurotypical people intrinsically find neurodivergent people off-putting in some manner (read a study on it a hundred years ago). This world is not setup for us in any way shape or form. Regardless of what your doctor tells you, you are already against the grain if you're diagnosed ADHD. If you want to challenge the diagnosis, there's always more money you can throw at the situation. But seemingly, nothing will ever be handed to you regardless of the label. And it seems to be more of an internal wound-healing device than something the world as a whole gives a plop about =/!

Sorry this sounds so awful, I just have a chip on my shoulder because I always assumed getting diagnosed (which was also later in life for me) would make things so much better. But outside of internet spaces (and by this I mean spaces directly tied to being neurodivergent as a whole) it's been a detriment to speak on. And I have just put it in my back-pocket. Outside of having some joy in seeing others who may be similar in media from time to time (I don't really diagnose people in front of me because I am not an asshole). It seems something that should be celebrated as a joy of self, just ended up being another reason for people in everyday life to put a "broken" label on me and treat me differently than they would if I were of a certain way instead.

But that's on me, that's my bitter. So I suppose - don't let me ruin your party. Make your own decisions and form your own opinions around the situation =)

And, an answer of “get out of here you lazy git” would be a bit crushing at this point, precisely because the symptoms seem to fit and explain my life so well.

Been there, done that, was, as you suspect, crushing. But I was early in my journey and knew I was both new to the world of autism, and struggled to advocate for myself, so I kept at it, because like you say - everything just clicked, the more I read from and interacted with autistic people, the more I felt like my real self, and it perfectly explained everything I was struggling with (and also run wild and underdiagnosed in my family), you just know. Eventually I got "recognised" by a therapist and a gp, rather than go on a waiting list again for another year or two or pay privately to try and be "diagnosed" by different specialist. I've never been questioned about it since.

I am going to the appointment tomorrow though, no matter what. Will report back!

This is the best thing to do of course, it may very well go completely smoothly and you'll get the diagnosis and maybe even some support, but it's always good to be prepared in case it doesn't, and (easier said than done, for sure) try not to catastrophise.

Will definitely keep an eye out for an update!