If you think sex trafficking only happens in faraway places like Nepal or Thailand, then you should listen to an expert on American sex trafficking I interviewed the other day.

But, first, wish her happy birthday. She turns 16 years old on Thursday.

She asked me to call her Brianna in this column because she worries that it could impede her plans to become a lawyer if I use her real name. Brianna, who grew up in New York City, is smart, poised and enjoys writing poetry.

One evening when she was 12 years old she got into a fight with her mom and ran out to join friends. “I didn’t want to go home, because I thought I’d get in trouble,” she said, and a friend’s older brother told her she could stay at his place.

Brianna figured she would go home in the morning — and that that would teach her mom a lesson. But when morning arrived, her new life began.