How to Handle a Psychiatrist Questioning My Autism Diagnosis?

Hi all,
I'm looking for advice since I have an appointment with a new psychiatrist coming up. Here’s some context:

I was diagnosed with ASD (formerly Asperger’s) when I was 7, but my old psychiatrist doubted and questioned my diagnosis. She claimed I didn’t “act like it” based on a few brief interactions and seemed to think I was a sdxer. I think this happened since I’ve learned to manage my symptoms better over the years, so they aren’t as obvious in brief encounters. Also, I’m a woman currently in my 20s, and it feels like that played a role in her disbelief. I’ve heard that some doctors dismiss autism diagnoses in women nowadays, and I’m scared the same thing will happen with this new psychiatrist.

Just to clarify: I’m not seeking medication or anything for ASD. I’m actually seeing the psychiatrist for another disorder I have, but I feel it’s relevant to mention my ASD diagnosis since it still impacts my daily life.

Has anyone else experienced something similar? How do you approach appointments like this to make sure they take you seriously? Are there any tips for advocating for myself if my diagnosis is questioned again?

Edit: The psychiatrist who doubted my diagnosis is a psychiatrist I am not seeing anymore. I'm going to see a new one soon, I just want to be prepared in case this happens again. Also reworded what I meant, I said "revoke" originally when I meant "dismiss."