Long time coming, this one. Sorry about that.
My parents never told us a thing about sex. Under pressure, Mom told me the basics of menstruation, but nothing whatsoever about sex. This was completely the norm at that time. My sister L decided I needed to know more than she'd been told. One night she took me for a drive in the family car. I was probably nine or 10; she'd have been 16 or 17. She asked me what I knew about sex and if I had any questions. I remember telling her I already knew (which of course wasn't completely accurate) because my friends from school told me. She said I should always feel free to ask her if I had questions. She told me she wished Mom and Dad had told her more. She told me she'd basically been forced into her first sexual encounter and didn't want that to happen to me.