Rachel McAdams and the cast and crew reflect on why it was important to keep Judy Blume's classic 'Are You There God? It's Me, Margaret' timeless on the big screen

• Judy Blume's classic "Are You There God? It's Me, Margaret" has finally been adapted for the screen.
• Rachel McAdams, who plays Margaret's mom, told Insider she related to Margaret as a preteen herself.

Generations of young women who went through puberty grew up chanting, "I must, I must, I must increase my bust!" thanks to Judy Blume's classic chapter book, "Are You There God? It's Me, Margaret." The story follows sixth-grader Margaret Simon on her quest to start puberty, all while dealing with the upheaval of her family's sudden move from Manhattan to the New Jersey suburbs and trying to suss out her religious identity at the same time.

The book was originally published in 1970 but is only loosely tied to the decade. The long-awaited big-screen adaptation of the story, helmed by writer-director Kelly Fremon Craig and released in theaters nationwide today, could've easily been transplanted to a modern-day setting.

But in interviews with Insider, Fremon Craig and stars Rachel McAdams and Abby Ryder Fortson made a valid case for why the movie is better off staying set in the '70s and how it remains timeless either way.

McAdams, who plays Margaret's mom in the film, told Insider she related to the preteen protagonist

McAdams plays Margaret's free-spirited artist mother Barbara Simon in the film but told Insider that, like many young women, she recalls her tween years being very similar to Margaret's.

The Oscar-nominated actress recalled several of her own childhood memories that mirrored the character's experiences, like wearing shoes she hadn't broken in on the first day of school and "coming home with blisters and not being able to wear those same shoes for the next month."

In the book and in the film, Margaret also begs her mother to take her to the mall to buy a bra so she can fit in with her new friend group. McAdams said she had a similarly "awkward" preteen experience — and much like Margaret, she can only appreciate her mom's help in retrospect.

"I'm grateful that my mom was there and took me through that. But at the time, I wasn't," she said.

For McAdams, the film was important to make and keep timeless because Margaret's journey was "exactly the same" for so many people in so many generations, and seeing that struggle represented helps young people feel "not so alone."

Fortson, the standout young star who plays Margaret, told Insider in a joint interview with McAdams that she was going through the "exact same stuff" as the character at "the exact same time" she was on set and developing the character.

The teenager, who producer James L. Brooks told Insider beat out "literally thousands of kids" auditioned to win the part, said that, like Margaret, she's still trying to define who she is "every single day."

"I'm 15, and I know people who are 80 and still figuring themselves out," she mused, capturing the essence of why "Are You There, God?" has such a strong legacy.

Writer-director Kelly Fremon Craig kept the movie set in the '70s to make sure every woman watching felt 'connected' to Margaret's journey

Fremon Craig is no stranger to coming-of-age stories that push boundaries — her debut feature film as a director (which she also wrote) was 2016's "The Edge of Seventeen," starring Hailee Steinfeld.

Still, she called it "surreal" to be adapting a book she loves so much. Fremon Craig famously won the movie rights by writing an impassioned email to Blume, who'd refused any adaptations of it for decades, and the screenwriter told Insider she certainly felt the pressure to get the highly-anticipated adaptation right — for Blume, for Blume's fans, and for herself.

As a longtime fan of Blume's book, Fremon Craig decided she should stay "faithful" to the original story without giving it a 2023 update in order to best capture the spirit and feeling of the beloved classic.

"I can so vividly remember my 11-year-old self doing, 'I must increase my bust,'" she said. So, she kept in subtle references to the '70s, while also leaning into the timelessness of the subject matter.

"I think that there's something really neat about girls today going to watch this movie and realizing that everything they're going through, girls went through 50 years ago. Their mom went through it, their grandma went through it," she said. "All women throughout history."

"Are You There God? It's Me, Margaret" is in theaters now.