It’s not easy to break into a 143-year-old business. Just ask the boss’s daughter.Trisha Joseph’s first experience working at Josephs Jewelers—the fine jewelry business owned by her father, Toby Joseph, and her uncle, John—didn’t exactly point to her future vocation as co-owner of the West Des Moines, Iowa–based retail chain. “I worked as a gift-wrapper during the holidays when I was in high school,” recalls Trisha, who studied psychology at the University of Iowa before stints as a preschool teacher and in hotel management. “I never thought I’d join the business; I thought I was going to go to graduate school.” She and her brother, Jake—who’s also now a co-owner—­currently manage one of Josephs’ three locations. Jake, who initially thought he would go into engineering or a ­computer-related field, earned his undergraduate degree in accounting:  “