re: Who can remember their entire life?

only back to age 4. a few incidents.
from 7 on I can recall more but no word for word conversations like you.
I don't think I ever could recall whole conversations.

you could have been the guy who hears the Iliad once and recites it to a Greek city in Sicily.

I got through trig by memorizing. I didn't know how trig worked until my daughter was in high school and I read a tutorial on the Purdue website.