“I feel like you have to take any amount of sadness with a measure of joy,”

Iain, 15, told reporters on the Los Angeles set of the show.

“[I’m] very sad to be almost done, but so happy and so grateful.”

Iain was 8 years old when producers Chuck Lorre, Steven Molaro,

Steve Holland and Jim Parsons, who played Sheldon Cooper on Big Bang,

cast him in the prequel. The final season, airing Thursdays at 8 p.m. on CBS, will conclude with Sheldon at age 14.

The Big Bang Theory picked up with Sheldon as a Cal Tech theoretical physicist

living with fellow scientists. Though a decade or more still exists between Young Sheldon and Big Bang, Iain said he considers the real-life Parsons more of a role model than Sheldon.

“If I can grow up and be as wonderful a man as Mr. Jim Parsons is, I would be very happy and feel very accomplished in life,” Iain said.

Nor is he worried that spending seven years as Sheldon will typecast him for future roles.

“Honestly, if that happened I wouldn’t be mad,” Iain said. “I would love to be associated with Jim Parsons forever.”

The cast of Young Sheldon found out Season 7 would be their last on a Zoom call before the season. Iain said he took the news well.

“I feel very lucky and very happy that we get such a nice and gentle closing,” he said. “We get to really wrap this up the way it should be.”

In the seven years since Iain first met reporters to discuss Young Sheldon, he said the difference at age 15 is that now “less jokes go over my head.”

Though Iain now has more of a body of work to discuss with adult reporters, he said his enthusiasm for discussing Young Sheldon remains as high as ever.

“I have just as much fun now, if not more, than I had when I was 7 or 8 or 9,” Iain said. “I feel very grateful above everything else.”

He said he has learned from all of his co-stars over course of the show, adding that his favorite memories have been dinner scenes that involve the entire Cooper family.

“They can sometimes be annoying because there are so many camera angles, so many people, but they’re always so fun and so crazy,” Iain said. “I hope I can be as good with everything, especially acting, as they are.”

His education has been different from Sheldon’s accelerated learning pace. As a child actor, Iain attends to studying requirements during breaks in shooting.

He said pauses in work for COVID-19 shutdowns and the writers’ and actors’ strikes gave him a chance to get ahead on schoolwork. However, he does not plan to graduate early like Sheldon did.

“I’m proud to say I’m a straight-A student and I’m a bit ahead of where I would be normally,” Iain said. “I could pretty much graduate this upcoming year if I wanted to, but I think I’ll probably stay in and keep learning things that I’m interested in.”

July will mark Iain’s 16th birthday. With the milestone approaching, he said he is thinking about learning to drive, but plans to take it slow.

“I’d certainly like to get my learner’s permit, then maybe practice as much as I can and then get my license,” Iain said. “You don’t want me on the road.”

Season 7 begins with Sheldon attending an academic program in Heidelberg, Germany, with his mother, Mary (Zoe Perry). Once they arrive, Sheldon and Mary get the news that the family weathered a tornado back in the States.

Sheldon is more shaken by superior intellects among his teachers and classmates than the news that a tornado blew his grandmother’s (Annie Potts) house down.

“I loved getting to speak some German in these upcoming first few episodes,” Iain said.

An upcoming episode also features a TARDIS from Doctor Who. The TARDIS sat on the soundstage just outside the set of the Cooper house, but producers were cryptic about how a time machine from the British sci-fi series enters the world of Young Sheldon.

“It’s not going to be too big, I’ll say that,” Iain offered. “It’s going to be a very funny part of the episode.”