I know somebody well who works in children's mental health at a highly qualified professional level. They agree that, if they were a child now, they would be diagnosed as on the spectrum but feel that they have probably succeeded more by not having a label than if they had been diagnosed. They are, however, far more intelligent and high functioning than most of us
I can relate to a lot of this. My DD isn't diagnosed because she pulled the plug just as we were finally getting somewhere. We had our GPS backing, DD came to us asking to look into ASD at 14 & by 17 refused diagnosis. Having looked into it with her & joined a ASD parenting group I realised that we missed it. Partly because she's very high functioning, was ahead in all of her mile stones etc is very intelligent so does well in school, so there was never any worries at school etc. Friendship issues later yr 4/5 onwards, but by then she had other diagnosis that made her "different". Plus her quirks weren't so unusual in me/my family or DHs either.
To the OP...
Learning about HFA in high functioning girls for DD, I can so see that I was far more of a classic case for assessment in school than she was. I also did well, but I didn't speak till about year 8 & I was the weird kid, working on solving perpetual motion, obsessed with manatees, digging in the tip to collect vintage bottles & winning adult art contest etc when in primary school. Plus I remember the fights with DM over clothes & shoes & scratchy sheets
I can see that I have definitely experienced symptoms of ASD all of my life, though it could be due to the things too, but I've never let it stop me. I've had a good & successful career as a designer , enjoyed partying with good friends that I still have decades later, but realise that like I see DD doing now I found the fabulously oddball alternative crowd. Travelled the world, many times on my own & enjoyed every minute of the freedom of lone travel.
Unless living with a partner, I've always needed to live on my own though, I needed a quiet boat hole or I got exhausted & I'll very quickly. I realised at 21 when moving to London to live with with 4 girlfriends & lasting only a week before I had to make my excuses & leave, that I needed my own space.
Diagnosis would have made no difference to me back then, there would have been no support & ignorance would have meant the diagnosis would have likely held me back.
Now though, I'm not so sure. I'm disabled, I hit burn out shortly after DD was born & never fully recovered, later diagnosis with EDS & PA as is DD, so I didn't think too much of it other than I'd managed until I hit a major stressful time around DDs birth & couldn't understand why I couldn't pick myself up again as I'd had both of these genetic conditions all of my life & managed just fine, even if I did realise that I'd always had some more minor symptoms.
Reading about autistic burn out though, I can relate to a lot of that too. Maybe knowing about it all sooner & working with it better, might have saved me some health issues. Diagnosis wouldn't have helped though, the knowledge would have.
There is a lot more support & acceptance now though, so actual diagnosis might be more helpful to you now than it would have been for me.
I'm interested to see what others have to say though, as a diagnosis would certainly help us with DD, as we could hopefully get help with her sometimes very difficult behaviour. She's refused, which is her prerogative, but we do worry that she misses out on support too. But I was okay, so she may be too & she already has to work around her other diagnosis & gets some support for that, so hopefully she will be more sensible & won't burn out