Complex sentence: Jason Trost first had the idea when he was 16 years old, developing it into a short film starring himself, Valmassy, Principe, DeBello, Brandon Barrera, Diane Gaeta, Kris Lemche, and Torrance Haynes.
Split into simpler sentences: Jason Trost first had the idea when he was 16 years old. He developed it into a short film starring himself, Valmassy, Principe, DeBello, Brandon Barrera, Diane Gaeta, Kris Lemche, and Torrance Haynes.