My father was a heavy smoker, but none of my brothers or sisters, or I, smoked when we were
young. This did not seem odd to me. It was just the way it was.
Adults smoked. Children didn't. I wonder why your girlfriend didn't take that tack.
I remember once, when I was chaperoning a school dance, that someone took issue with me for smoking. She said the children weren't allowed to, so I shouldn't. I said I wasn't a child.