I got diagnosed with autism as an adult and I second your experience. It has been super-helpful to know what is going on. Especially since I am very repressed and an internalizer, so I spent my life struggling in silence, which sometimes made me gaslight myself about whether I even struggle at all.

I personally don't disclose to people who I assume wouldn't understand, but I don't feel ashamed by the label itself at all. I do feel ashamed by some of my autistic personality traits because of the negative feedback I got, but that happened BEFORE anyone, myself including, knew I was autistic. Because the stigma isn't (just) about the label, it is about the manifestations of the differences/struggles I inevitably do present and worked so hard to keep under the lid.

Personally I would feel so patronized for not getting the truth because my diagnostician decided I couldn't handle it. A friend got diagnosed with borderline personality disorder recently, or so she thought - turns out her former psychiatrist had already diagnosed or strongly suspected, without informing her. She scrutinized her after receiving the diagnosis from the new person, found out that former provider had known all along, was understandably upset and only now got to access specialized group therapy, which it turns out, helps her tremendously - more than any other form of treatment she had received. Because these labels make you eligible for more targeted support and allow you to connect with people in similar situations. And especially finding community has proven helpful in almost all documented cases.