Armitage was eight when he was cast on The Big Bang Theory spinoff. He'll turn 14 in July. So Young Sheldon is growing along with its star, as it begins to focus on more mature storylines that come with the teenage years. “It’s hard to believe that we started out the pilot (in 2017) when Iain was eight years old,” says Steve Molaro, who co-created Young Sheldon with Chuck Lorre. “And Raegan Revord, who plays Missy, was eight or nine. So we’ve come a long way. Back then we were doing more family-oriented stories and kid-friendly stories because we had two nine-year-olds on the show. But now that they’re young adults and teenagers, we’re finding we can really open up the kinds of stories we’d like to tell and let things get more adult with everybody. And that evolution has been really fun for us.” ALSO: Molaro didn't like Young Sheldon as the title: "Here we are five years later. It wasn’t a loss. It’s here, it is what it is."