Author Veronica Roth. (Nelson Fitch)

A trilogy, a 16-year-old girl, a first romance and a movie deal. On the surface, Veronica Roth’s “Divergent” trilogy reads like another in a long line of fantastical young adult fiction. But the world Roth creates deals with humans, not vampires, werewolves or genetically mutated dogs. There are no bows and arrows; guns and knives are her weapons of choice. And at 25, Roth is constantly surprised at the impact of the story she started writing during her freshman-year psychology class.

Divergent,” the first book in the series, follows Beatrice “Tris” Prior as she makes the transition from childhood to adulthood. In this version of dystopia, this means choosing one of five “factions” that make up society (Abnegation: Selfless, Dauntless: Fearless, Candor: Truth-tellers, Erudite: Knowledgeable and Amity: Peaceful). Tris chooses Dauntless. But like most major life decisions, the choice is just the beginning. Tris sets in motion a war that follows her and her first love, Tobias “Four” Eaton, into the second book, “Insurgent,” and is the catalyst for a pending revolution in “Allegiant,” to be in stores Oct. 22. (The book leaked earlier this week when a shipping error caused a select set of pre-orders to be delivered three weeks early.)

“The idea of having them really trapped in a faction is something I’m familiar with because I struggle with anxiety. Tris does what I’m always working to do. She makes the bold move. That’s where the inspiration came from,” Roth says.

And to her young and not-so-young adult readers, Roth’s age and mental-health struggles complete the trifecta that has led to the sale of more than 4 million copies of “Divergent” and “Insurgent” and inspired “The Transfer,” the first in a series of e-book short stories told from Four’s perspective.

“I was in New York for ‘Insurgent’ and a girl came up to me and told me she got a dauntless-inspired tattoo because of her struggles with anxiety. [The word “dauntless” with birds surrounding it. The same birds that fly across Tris’s collarbone.] To her it represented bravery and facing her fears — hearing that was so inspiring,” Roth says.

Book cover for the novel "Allegiant." (HarperCollins)

This connection echoed last month in the District, when Roth spoke to a packed tent during the Library of Congress’s National Book Festival.“It’s wonderful to have a smaller gap between me and the readers. It’s still fresh — being that age,” she says. “These are my people.” And to the shaky-voiced teens who asked question after question, she was theirs.

Your characters are really realistic. Are they based on real people?

“None of my characters are based on real people. Everyone has little pieces of me, even Jeanine [The role Kate Winslet has signed on to play in the “Divergent” movie set to be released in March 2014] — granted, it’s the worst parts.”

As a young author, do you have any tips for authors?

“Write a lot, all the time, about what interests you and write from your gut. It’s important to show your work to people, but choose people you trust to be kind with their criticism.”

Tris seems a little unstable. Is she?

“She does something traumatic and bad at the end of book one. I wanted her to deal with it in real ways.”

What will you write next?

“I love the speculative-fiction area and I love writing for this group [young adults], so I’ll probably try the spaghetti method.”

While the end of Tris’s journey is eminent, Roth’s is just begining, leaving many readers wondering which of her words will stick with them next.