Same here in the UK.

Maximum target waiting time is 13 weeks - AFTER you get a referral from a GP - and not all of those are willing to refer adults who are high functioning because they see it as taking a rare resource away from those more in need.

But even with that referral, 84% of people are waiting longer.

Private is possible, and 3-4 weeks, but that costs around £4,000.

Without a professional diagnosis, you won’t qualify for any assistance, either from the state or your workplace.

(I self diagnosed as autisitic in my 50s, after a childhood diagnosis of dyslexic. I now think was a misdiagnosis of autism.)

self diagnosis is valid.

I agree. And in my country, waiting lists for any professional diagnosis are extremely long, especially for adults.