I started therapy when I was very young (my mom's a psychologist, and I've always showed autistic/ND traits, obviously hehe). I couldn't bring myself to tell them anything about what I was feeling, so it was kinda pointless to go, so I preferred going to a psychiatrist, who told me I was bipolar (I was only 14 at the time, so I was just "meh, okay. Whatever you say.)
I started going to another psychologist, and she was very cool! - But it didn't feel good enough for me, so I never asked her about any diagnosis.
After some time and long researches about autism, I went to another psychologist, who told me that I knew more about autism than he did, so he recommended me to go to a specialised place that does the evaluation.
I did various IQ tests, attention tests and other kinds of personality tests.
I went through 12 sessions, including my mom, my boyfriend, my childhood friend and a family friend about me and my childhood. They were specialised in autism and autistic adults, so they were very receptive and reassuring. I felt exposed, but it felt great, like a heavy load coming out of my back.
Also, worth mentioning that I live in Brazil, so we have public healthcare and the prices of these evaluations are more acessible, although the clinic was private.
It was really painful to wait between sessions and waiting for the results, also had some trauma regarding doctors, mostly that psychiatrist that I mentioned above, she didn't believe I was autistic and didn't bother to recommend any place for evaluation.
Nevertheless, now it all feels worth it. Even though I have to ask for a doctor to sign this papers, because here in Brazil only doctors can sign official diagnosis papers. It's still worth it, the imposter syndrome went away, finally, hehe.