Jenny Han Says Prime Video's 'The Summer I Turned Pretty' Was 'A Long Time Coming'

After years of being approached by producers and writers eager to adapt The Summer I Turned Pretty, Jenny Han was resolved only to move forward with the project if she could adapt the book herself.

"There had been interest over the years," she tells PEOPLE. "But I always said no, and now I think it's because I actually really wanted to be able to do it myself — and to do it the way that I envisioned it."

After serving as executive producer for the second and third installments of Netflix's To All the Boys series based on her bestselling book trilogy, Han says she learned a lot about the adaptation process. With that knowledge, she was certain she wanted Summer to be at TV series that she could shape.

"I think that TV writing is more novelistic," she says. "Being able to spend time with the characters and see the growth over seven episodes, I think you just get to know them so much better."

Television also favors the writer, who "holds the story in their hands the whole way through," she says. Han, 41, is particularly hands-on in the Prime Video series, serving not only as writer but creator, co-showrunner and executive producer.

The Summer I Turned Pretty follows Isabel "Belly" Conklin (Lola Tung) over the course of a summer in Cousins Beach spent with her older brother, Steven (Sean Kaufman), and the Fisher boys, Jeremiah (Gavin Casalegno) and Conrad (Christopher Briney). The multigenerational drama sees Belly navigating a summer of firsts. Her first love, Conrad, seems to start to really see her this summer, while the younger Jeremiah has always seen her.

All the while, Belly's mother Laurel (Jackie Chung) and the Fisher brothers' mom Susannah (Rachel Blanchard) spend the summer navigating their own major life changes.

While the book was told from Belly's point of view, the show follows each of the characters with more depth — including Laurel and Susannah, whose lives weren't exactly at the top of Belly's mind in the books.

"I was really interested in seeing women at different points in their lives, coming of age," Han tells PEOPLE. "Belly is coming of age, and so is Laurel — coming out of a divorce, and she's about to be at a big emotional crossroads where her life is changing in really big ways."

The show, which Han says is "more about a feeling, and a vibe, and the aesthetic" compared to her Netflix adaptations, introduces a brand-new slate of actors, many of whom are making their on-camera debut. Han says the newness bonded them, and that translated onto the screen, too.

"What was so special about the show experience is how the actors really became this close-knit family. I know everyone says that, but we were in this little beach town in the height of COVID and kind of just had each other," she recalls. "I think you really see that on the screen. I think you see that intimacy and closeness and love for these two families."

As the central character of the series, Belly was the first role to be cast, Han says. She was looking for someone to represent the innocent, child-like charm of the 16-year-old. "It's not about the way someone physically looks, but it's just a feeling about them — that they're still sort of new in the world."

While they were fortunate enough to have a wealth of options for the lead, Han says 19 year-old Tung stole her heart almost immediately. "I kept on looking at Lola because she just made me feel something when I watched her," she says. "I felt like I was rooting for her."

The author says it was almost "meta" seeing Tung acting out the scenes, because she found herself rooting both for Belly and for Tung herself. And while this was the Carnegie Mellon student's first major role, Han says she was the perfect Belly.

Han is careful not to give away too much about the show despite excitement from her readers ("It's been a long time coming," she says, "the books came out 13 years ago!"), but she promises that a few key moments from the book will make their way into the adaptation — including the infamous Belly flop.

For longtime fans worried about whether Prime Video's telling of the story will live up to their expectations, Han understands the fear: "Reading is so personal, and so people get so nervous about adaptations" — but no matter what, she says, "that reading experience is always going to be yours."

"Nothing will really match up to the story that you saw in your own head when you read the book, but you will always have that experience, and that will always be alive for you in your imagination," she says. "This is just my version of The Summer I Turned Pretty TV show, how I envisioned it and how I wanted to tell it."

The first season also brings some new storylines — and new faces — to Cousins Beach, all of which the creator hopes will help expand Belly's world during this pivotal summer in her life.

"I approached this adaptation like, how do I tell the story in 2022? It's all the same characters and the same essence of everybody, but how would that character be in 2022?" Han shares. "I was writing these books starting in 2006. It's been quite a long time. Culture has changed in many ways."

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Even with some new additions to the story, The Summer I Turned Pretty still has Han's magic all over it — so much so that Prime Video has already renewed the series for a second season.

"Getting picked up for season 2 before the premiere of season 1 is such an exciting vote of confidence from our partners at Amazon," Han tells PEOPLE in a statement after the renewal news. "We're already hard at work on the next chapter of Belly's story, and I can't wait for everyone to see it!"

She says the first season is just the beginning of Belly's story — and the boys' too.

"Belly is messy, and she makes a lot of mistakes, and so do the boys, too, but I'm eager to see her continue the journey and keep growing up."

The Summer I Turned Pretty premieres Friday on Prime Video.