THE end of the road for CBS’ “The Big Bang Theory” is coming into closer focus. The nerdy series ranks as TV’s most watched comedy among the advertiser-coveted adults 18-49 demographic and was renewed in March for its 11th and 12th seasons (48 episodes in total). “We never really figured to be at year 11, let alone what’s going to happen after 12. One could easily presume that would be the end of the series, but I’m just amazed we’re here,” co-creator Chuck Lorre said after presenting spinoff “Young Sheldon” to the press this week at the Television Critics Association’s summer press tour. “Big Bang Theory” does not plot out storyline arcs in advance, a change from how most television shows are traditionally produced. Executive producer Steve Molaro — who recently stepped back as showrunner to focus on “Young Sheldon” — was more reluctant to address the show’s future. “We look at one episode at a time, that’s what we’ve been doing for the last 10 years and it’s gotten us this far,” he said. Asked whether season 12 was the end game for the comedy, new CBS Entertainment president Kelly Kahl offered a more open-ended approach to the future of the series. “As long as we can go; 20 years. I hope to have it as long as we can,” he said. “Young Sheldon” revolves around Sheldon (Iain Armitage) as he lives with his family in east Texas and attends high school in 1989. Zoe Perry stars as Mary, Sheldon’s mother, and takes on the role from the flagship series that has been played by the actress’ own mother, Laurie Metcalf. Lance Barber is George, Sheldon’s father; Reagan Revord is Missy, Sheldon’s twin sister; and Montana Jordan plays George Jr., Sheldon’s older brother. Annie Potts recently joined the cast as Sheldon’s beloved grandmother Meemaw. “We’ve been talking about this story on ‘Big Bang Theory’ for 10 years. The origins of Sheldon have been something we’ve been interested in writing about,” said Lorre. Jim Parsons, who plays Sheldon on “Big Bang Theory,” also serves as narrator on “Young Sheldon.”(SD-Agencies) | 