I self diagnosed but it still felt unexpected if that makes sense? I stumbled on a blog run by a psychologist who specializes in a number of neurodivergent conditions and got caught up looking at the similarities and differences between autism and ADHD [a condition I was diagnosed with already] and it made me realize two things 1: ADHD had been severely downplayed my whole life and how I was forced to cope with it with no help was unfair and 2: I had symptoms from all over the symptom venn diagrams for autism and ADHD but when comparing it to most of the other condition venn diagrams I only had shared symptoms or symptoms that fell under the half describing autism or the things I already had diagnosed. It blindsided me and I ended up going down one of the biggest research rabbit holes I've ever gone down, which says a lot, the entire time going "holy shit i have autism????"
Then i started noticing and experiencing some severe symptoms and traits while feeling like i couldnt remember a time in my childhood that I really showed that many symptoms and I started thinking that I was wrong or that something else had to be wrong to have caused these symptoms so suddenly. I started stimming more and more noticeably for different reasons and I felt like I didn't do it that much or for those reasons before. I thought I never had issues with holding eye contact before, no one complained i wasnt and it hadn't made me uncomfortable that I had noticed. I thought i was having more issues with noises and light than before. I thought I never had an issue with introspection and suddenly i was relying on a dog to tell me when to pee and eat. I thought my social interactions have gotten weirder and less stable and easy to maintain. In reality though? It took me literal years to realize it all but I have always stimmed quite a bit, but the slight increase after learning I was autistic was more that I subconsciously knew itd help in new situations that I didnt think itd help before and i let myself do it more. I've always disliked eye contact so much so that when I was fairly young an adult in my life told me that if i didn't want to make eye contact I could just look at the center of people's eyebrows or their nose and they cant tell, I took it to heart so much that I tricked myself into thinking that I was making eye contact with people instead of staring at people's foreheads for so long it took until i was analyzing it to realize something is wrong. The funny thing is I've since been told that close up my eye contact is "weird" because i cant pick an eye to look at and end up darting between both so if I had been making eye contact someone would have pointed that out earlier. My earbuds broke and i was regularly in a new, brighter, environment than I was used to shortly before I found out about my Autism and the stress from that continued to build until i figure out the issue and I got new earbuds and asked professors to lower the lights. Before I had my dog to tell me when to pee and eat I was getting frequent bladder infections and UTIs because I was always holding it and acting as if that were normal for some reason and I would eat less than a meal a day on adverage, something I fully blamed on meds that I no longer take and an ED that I have managed but still have a pretty serious issue with unless I just eat with my partner or listen to the dog. And my social interactions DID get weirder, I stopped masking a little subconsciously because it was tiring but also i was transition [ftm] and still can't figure out how to mask in a masculine way. But I was also weirder and more wrong in social situations than I thought and every day im barraged with memories of a social screw up that I now understand made me look mean or intimidating or awkward or I learn a new social thing I've been misunderstanding and therefore also using incorrectly my whole life because I couldn't read the tone around it.
Sometimes it takes a long time and a lot of digging around in yourself, feelings, and memories for everything to be put into perspective. Sometimes that perspective points to a misdiagnosis and sometimes it just confirms what you've already been told or already knew.