Hi @Former-Member and @Former-Member,
ASD is definitely not a mental illness, it is a neurodevelopmental disorder. At least, that's what the "experts" say, but really, it is simply a different way of being in the world. I tend to use the term neuro-atypical (and thus I use "neurotypical" to describe people without ASD).
I figured out a few years ago that my issues couldn't all be explained by my psychiatric diagnosis of borderline personality disorder. Over a couple of years I put together the pieces of the puzzle and figured out I had ASD. I then paid for a formal assessment because no-one believes you unless an "expert" has made the diagnosis.
ASD is often missed in females because it presents differently to in males. I know my life would be very different now if one of the bazillion mental health professionals I've seen over the past two decades had picked up the tiny little detail of AUTISM. Grrrrrrrr!!!!
There is an organisation in Australia called "yellow ladybugs" which is specifically focused on ASD in girls (and women). A quick google search will help you find them. I hope that helps @Former-Member. 