Meghan Markle is looking back on an unexpected moment that brought her Girl Scout days rushing back.

The Duchess of Sussex is opening up as Cookie Queens—the coming-of-age documentary she and Prince Harry executive produced through Archewell Productions—heads to theaters on Aug. 7, marking the company’s first theatrical release. Directed by Alysa Nahmias, the film follows four Girl Scouts as they navigate the highs and pressures of cookie season while learning confidence, resilience and leadership.

Meghan, who is celebrating her 45th birthday on Aug. 4, says working on the documentary reminded her of her own childhood as a Girl Scout—including a sweet surprise she experienced during 5-year-old daughter Princess Lilibet’s first day of preschool.

“Funny enough, on Lili’s first day of pre-K, one of the moms came up to me at drop-off, and I realized we were in our troop together!” Meghan tells PEOPLE. “It was so sweet and nostalgic.”

The memory struck an especially personal chord for Meghan, who was a Brownie and Junior Girl Scout while growing up in Los Angeles. Her mother, Doria Ragland, even served as her troop leader.

Now, as the mom of Lilibet and 7-year-old Prince Archie, Meghan says revisiting that world through Cookie Queens brought back “great memories” while reinforcing the importance of empowering young girls.

“These girls are our future leaders and amazing role models,” she says. “I found this element of the film so important; showing young female entrepreneurs, girls with financial literacy, skills that will set them up for future success, and learning how to work to achieve their goals is so inspiring.”

For Meghan, those lessons have only taken on greater meaning with time.

Asked whether the film resonated differently because she’s raising a daughter, she didn’t hesitate: “100 percent.”

The sentiment echoes what Meghan previously told PEOPLE while launching her As ever brand last year, when she said she hoped Princess Lilibet would grow up watching “what it’s like to be a working mom.”

“Being able to have my own little girl, as I’ve spent so much of my life championing the rights of girls and women … I love the heritage feeling of it and knowing this is something that I can create in front of my daughter,” Meghan told PEOPLE in 2024. “This is something that hopefully can be part of her legacy too.”