On Saturday at 8:15 p.m., the Bronx Documentary Center, 614 Courtlandt Ave., is showing “P-Star Rising,” a new documentary about Priscilla Diaz, a New York City product who started rapping at an early age and eventually became a television star. The film follows her over the course of four years. After the showing, there will be a Q & A with Diaz and the film’s director, Gabriel Noble. Above is the trailer for the film.