I’m now 61 and my life experience mirrors yours in a lot of ways.
Both my daughter (very similar to me and already diagnosed) and my SIL (foster carer and social worker) have both said that I am autistic. Online tests agree too but it’s a while since I’ve done one and can’t remember the actual results.
Having said all that, I really don’t feel that an official diagnosis is even worth bothering about and I certainly wouldn’t be considering spending £2k plus on it.
I am who I am and a piece of paper isn’t going to change anything.