If Mia (Chloe Grace Moretz) chooses to live, her guy (Jamie Blackley) won’t be the deciding factor. (Warner Bros/MGM)

In “If I Stay,” the new film based on Gayle Forman’s 2009 book, teenage Mia has a big choice to make. A really big one.

After being seriously injured in a car accident that killed the rest of her family, comatose Mia (Chloe Grace Moretz) can either move on to the afterlife or stay in a world that promises intense loss, endless physical therapy, and what’s probably a probate nightmare.

Oh, but she does have a boyfriend. Which — surprisingly in a film based on a young adult novel — isn’t actually that big of a motivator for her to come back to life.

“I would never have chosen a movie like that,” says Moretz (“Kick-Ass,” “Carrie”). “It’s just so cliche. And I didn’t want to do a movie that was, like, ‘audience, cry!’ I wanted to make a story about life and love.”

While the main conflict lies in Mia’s choice, the movie weaves together flashbacks of her life, of which her relationship with beau Adam (Jamie Blackley) is just a part — an important part, but just a part.

In that life, Mia is a talented cellist aiming for Juilliard, she has a happy family, she has a best friend. She just happens to have a boyfriend, too.

That wholeness of Mia’s life is what drew Moretz, something of a film veteran at 17, to “If I Stay.”

“In this you see just a period of time in someone’s life and you just see a normal girl,” she says. “And most normal girls have a semi-normal family, they have some sort of extracurricular they fall in love with, and they get a boyfriend. But this story’s not about the boyfriend.”

It is all about love, though, the author of the source material says.

“I see the book and the movie as a series of love stories,” Forman says. “It’s familial love, there’s also a romantic love and music love and friendship love. It’s about the tapestry of her life and about how that tapestry is destroyed.”

And, ultimately, about whether Mia chooses to wake up and start reweaving.

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