@tardis I would say you don't need a diagnosis, and I speak as someone who has one.
It helped me in the work world, but no more than a note from my doctor did, and I could have just gotten the note from my doctor.
I get more help from my fellow autistics online than I ever did from my official diagnosis.
Neurodivergent peoplestic know neurodivergence & it's different for everyone. That's who I listen to now.