why would she want to earn money while supporting the family business?
and as I said, it's unclear whether it's "adult bookstore" or "bookstore with an adult section"
A dad who wants cheap labor, or wants to keep money in the family, and isn't bothered by arbitrary rules.
I mean it's pretty silly to clutch pearls over this. They're high schoolers, they're sexually mature and aware, she's already had a girlfriend who used sex toys so has likely had sex. You think she's going to be damaged somehow by this, in a way that magically stops on her 18th birthday?