Look up some youtube videos which break down the criteria a bit more, making them easier to understand. I think Yo Samedy Sam has a good one, I also have a book called I think I might be autistic (link) which breaks it down very well (even if it is a little outdated now). The book is quite good in saying how the severity is important.
As I recall, this book had a very good compilation of therapies with expected outcomes in the end. The prose is intended for adults, but the therapy advice should still give you some understanding. https://www.amazon.com/gp/product/0989597113/ref=ppx\_yo\_dt\_b\_search\_asin\_title?ie=UTF8&psc=1
I am a 48 year old female and I have always believed that I am on the spectrum; especially in social situations. I also happen to work with children on the Autism spectrum, so I know how people on both the mild and more severe end of the spectrum act. I bought the book "I Think I might Be Autistic... for Adults" on Amazon, which has a questionnaire you can take to help you decide if you might be on the spectrum. When you finish the questions, they don't give you a formula to figure out if you are on the spectrum, but if you answered yes to many of the questions, they tell you to go get an official diagnosis. I didn't bother with that and mathematically I figured out that I answered yes to 28% of the questions, which in my mind, puts me on the spectrum. https://www.amazon.com/gp/product/0989597113/ref=ppx\_yo\_dt\_b\_asin\_title\_o08\_s00?ie=UTF8&psc=1
> I grew up in a home where it wasn't ok to be anything less than perfect and my father would never allow something to be 'wrong' with his perfect child, so it was never even a possibility.
I was hit if I stimmed or did anything weird. They mostly beat the autism out of me and I resorted to stimming methods they couldn't see. As long as I acted a certain way it was okay.
That translated to fear later on. Fear that would drive such intense inertia that I couldn't move forward with figuring this out.
My partner bought me this book: https://www.amazon.com/Think-Might-Autistic-Diagnosis-Self-Discovery/dp/0989597113/
I wrote notes on all the pages about things in my life that relate. It was pretty eye opening. Having a tangible book where I was reading and jotting down my thoughts on the matter was the first big step.
That book with the notes I took and the pages book marked and highlighted was a resource. I could bring it with me to appointments to demonstrate what I'm thinking.
There are a couple of books on Amazon UK.
I Think I Might Be Autistic: A Guide to Autism Spectrum Disorder Diagnosis and Self-Discovery for Adults https://www.amazon.co.uk/dp/0989597113/ref=cm_sw_r_cp_api_SCPIxb4TH3Y4Y
and Sensory Issues for Adults with Autism Spectrum Disorder https://www.amazon.co.uk/dp/1849056617/ref=cm_sw_r_cp_api_ODPIxbG8DPSRT
Both have kindle versions.
You will want to check with your GP to rule out other causes, and research health insurance coverage for testing. Mine covered it, but many don't. Then, you will want to schedule an appointment at a covered provider.
The process takes a lot of time (10 months for me), and can be costly. They will also discuss some other possibilities that may be scary (brain tumors and schizophrenia were discussed in my case). Don't give up though, knowing can make a big difference in quality of life (and will improve later medical care).
This book was recommended to me after diagnosis, but may help you: https://www.amazon.com/Think-Might-Autistic-Diagnosis-Self-Discovery/dp/0989597113/ref=tmm_pap_swatch_0?_encoding=UTF8&qid=1611200312&sr=8-1
I found this book helpful as a starting tool. It's very short so it's a good starting point.
https://www.amazon.com/Think-Might-Autistic-Diagnosis-Self-Discovery/dp/0989597113
This book from Amazon has really good advice and a quiz that you can take to help you decide if you want to proceed with professional testing: https://www.amazon.com/gp/product/0989597113/ref=ppx\_yo\_dt\_b\_asin\_title\_o08\_s00?ie=UTF8&psc=1
I've linked this a bit, but it was recommended to me by my diagnosing psychologist and is helpful. https://www.amazon.com/Think-Might-Autistic-Diagnosis-Self-Discovery/dp/0989597113/ref=tmm_pap_swatch_0?_encoding=UTF8&qid=1611200312&sr=8-1
I don't want to overload you with too many book recommendations, so have you tried any of these four?
I Think I Might Be Autistic - Cynthia Kim
Living Independently on the Autism Spectrum - Lynn Soraya
Sensory Issues for Adults with Autism Spectrum Disorder - Diarmuid Heffernan
Been There. Done That. Try This!: An Aspie's Guide to Life on Earth - Various
I tend to recommend Musings of an Aspie. I think a lot of what she writes is very relateable for people who can pass as neurotypical more easily. The author, Cynthia Kim, also has an ebook specifically focusing on the diagnosis process for adults which you might find useful.
The other book I would recommend is The Complete Guide to Asperger's Syndrome. This one is much more comprehensive and delves a lot into childhood development as well. In my experience, you get a lot of "aha!" moments out of it from digging up childhood memories that suddenly make a lot more sense when viewed through the lens of a potential diagnosis.
I would also recommend checking out the Ask an Autistic videos on this Youtube channel. She presents them more as a guide to outsiders, but if you're new to all of this it can be helpful to get some understanding of ways it could impact you that you haven't consciously considered yet.
Finally, here's a self plug for my own blog where I've documented some of my experiences with my recent diagnosis journey.