The bowling world will be focused on the PBA Players Championship and its major title and $250,000 top prize this weekend at Bowlero Jupiter in southeastern Florida. But it won’t be the only serious competition at Bowlero Jupiter this weekend: Some of the biggest names in youth bowling will be competing in the inaugural PBA Jr. National Championship, most notably Jillian Martin, who last month was the brightest star of the PWBA Kickoff Classic Series. As I detailed in this story, 10...