How to get a diagnosis without childhood evidence?

I’ve been very easily distracted, couldn’t pay attention, daydreaming and unfocused since I was a kid. I never listened, was a mediocre student and had trouble making friends from like age 3.

I am finally starting a diagnosis process now at age 25, have been through two sessions but my psychologist mentioned she wants evidence from childhood before referring me to a psychiatrist, which i believe is standard practice. But I can’t get her any.

I will not have any statements from my parents, who are very forgetful themselves and have witnessed many of my “flops” since elementary school, they were even the ones to help me pick up my slack like drive to school since i was in 1st or 2nd grade because i would always forget my homework sitting on the kitchen table, or call up other kids houses to ask for the homework chapter bc i wouldn’t write it down in class. However they are older traditional chinese immigrants and do not believe in mental health or disorders. I have asked them multiple times and they basically said “wtf is this nonsense? don’t waste our time. no you aren’t autistic or whatever that is, now go study.”

I am not in contact with any teachers, no idea what their names are and most of them probably retired by now. I remember having a favorite third grade teacher who was very kind and understanding with my forgetfulness and she would stay after to help me, but she has sadly passed away many years ago now.

I have grades from college (could try my best to find high school ones but very unlikely… and def nothing from middle school or earlier …) but i don’t think that will be enough.

How do you get the diagnosis if you can’t provide evidence from parents/teachers?