Having arrived in California at age 7 from Guayaquil, Ecuador, Agustin offers a rare glimpse into the world of an undocumented student in his new memoir, “Illegally Yours,” published by Grand Central Publishing and available at Barnes & Noble, Amazon and other retailers. Known for his work as a writer on the TV show “Jane the Virgin,” Agustin, 41, now serves as the CEO of the Latino Film Institute, which hosts the annual Los Angeles Latino International Film Festival.