I waited months without hearing anything and with no idea even if anything was happening, but today I finally got the letter confirming my phone appointment.
It says they will mostly be asking about my childhood and school years, and might want a family member to talk to, which isn't possible, so I hope it will be OK. I don't really remember my childhood very much so I'm worried now. I thought the diagnosis would be about the way I am now, but it appears it will be mostly about how I developed as a kid.