Getting A Late Diagnosis

I'm having a problem with my GP, he won't refer me for an autism assessment because in his eyes ( and the second opinion doctor ) people my age are rarely diagnosed because it's always caught in childhood.
I know that's not true, more and more adults are being diagnosed.

I had been seeing a psychiatrist a few years ago and he leaned on thinking I have BPD ( I looked at his Twitter page, he seems like posting about BPD)


I researched BPD and though I did understand it, it didn't match what I go through or how I feel.
I've been called autistic since school, though I never knew what it was.
I was getting called the same thing when I joined college, so I started looking it up and they actually seem to be right. Not all of those people were being cruel, some said they had autism themselves or had family who did.


The GP won't listen, and I'm going to have a huge problem trying to pay for a private assessment.

What the hell should I do?