Well, the correct answer is that you need someone else, besides yourself, a professional that specializes in adult autism diagnosis, to do a comprehensive review of your history, perhaps interview someone who lives with you, perform a series of cognitive performance tests, interview yourself, and have you do some written tests.
I understand the logistical and financial reasonings behind a "self-diagnosis" and an "identity"...and there will be folks here that will disagree with me...but this is not a diagnosis. Having "autistic-like" experiences is not criteria for a diagnosis, in and of itself.
Autism is actually quite complex. It's a prenatal, genetic/epigenetic, neurodevelopmental condition that can have medical/physical health complications. It's not limited to the behavioral, communicative, and social symptoms we commonly associate with it. It affects the brain's micro-anatomy and physiology. There are even some blood tests like serum serotonin, homocysteine, glutathione, malondialdehyde, nitric oxide, cytokine, oxytocin, and vasopressin levels that can give clues towards an ASD diagnosis.
Personally, as an older individual, since my 40's, I have been working with my physician to help alleviate abnormalities in my lipid profiles, inflammatory markers, and blood pressure. It wasn't until I was 52, when I was diagnosed, and learned about all of these autism-related metabolic pathways, have my blood tested, and were able to adjust my regimen, get on the correct supplements, the correct medications, diet, weight control, etc in order to reverse much of the cardiovascular health concerns. I still have some mild kidney issues that we are still trying to get on top of. The point here, is that an ASD diagnosis also has some health implications to consider...something not often discussed...even within the medical community. Your doctor may be totally clueless.
You can take all the on-line tests there are, and they may suggest that you fall within the realm of autism, but those are only a small part of the diagnostics, and as such, should not be considered a diagnosis by any means. Our own cognitive biases being the contaminant of logic and truth.