When writing about teens, it’s important to remember the first rule: E is for emotion. “It’s not hard to get into a teen’s head, because it’s all emotions,” says Jenny Han, author of the popular young-adult series “To All the Boys I’ve Loved Before.” “Their feelings are amplified; you have no luxury of hindsight. If you haven’t had your heart broken before, you don’t know that you’ll be able to get back up again.”

Love in its many forms, by turns giddy, embarrassing and sometimes heartbreaking, are chronicled in the series, which has now been made into a movie starring Lana Condor as Lara Jean Song. Lara Jean is a 16-year-old Korean-American girl who keeps love letters in a teal hatbox given to her by her late mother. Lara Jean wrote the letters to all the boys she’s had crushes on, putting her feelings on the page and then tucking them away in her closet. But when the letters are mailed to their respective subjects, chaos ensues.

The experience of having her book brought to life on the big screen was surreal for Han. “I think as a writer you spend most of your time working on the book alone. When I visited the set and saw what a big production it was, it was overwhelming to see it come together.”

Lara Jean is a sweet character; a friendly introvert, she’d rather be at home watching movies with her little sister on a Saturday night than at a raucous party. Han, who is also Korean-American, said she definitely shares characteristics with her protagonist. “There’s some of me in all my characters,” she says. “I’m also pretty romantic at heart, and like Lara Jean, I like to spend time with my family and bake.”

And she’s thrilled that her all-American character has struck such a chord with her readership.

“Every time I get a tweet or an email that says that this book was the first time they felt seen or represented, that’s really meaningful to me, to give that experience to a young reader,” says Han. “All kinds of readers . . . have reached out and said they felt connected to Lara Jean. She’s a very warmhearted character. I wanted her to be in the vein of those classical children’s book heroines, and I was happy that she got that kind of reception.”