Gabby Douglas is high above the balance beam during practice at the AT&T American Cup at Madison Square Garden in March. (TIMOTHY A. CLARY/AFP/GETTY IMAGES)

In a shopping mall or amusement park, Gabrielle Douglas could easily be mistaken for a child who got separated from her parents. At barely 5 feet and 94 pounds, she could get overlooked entirely.

But when she’s flipping along a four-inch wide balance beam or whipping around the uneven bars, there’s nothing childlike about the competitor within this bundle of muscle, who may well emerge as one of the biggest stars of the 2012 Olympics.

For all her outward joy, the 16-year-old has wrestled with painful choices and given up a tremendous amount to pursue her dream of becoming an Olympic champion, including leaving her family in Virginia Beach at 14 to move to West Des Moines, Iowa, to train with the coach of 2008 gold medalist Shawn Johnson.

“It definitely has made me stronger and more mature,” says Douglas, who lives with a foster family and is pursuing her high school studies online. “And it’s temporary. I’m not going to be away from them forever.”

With a broad smile she glances at her mother, Natalie Hawkins, who accompanied her on a recent round of interviews, adding: “Our sacrifices are not in vain.”

Douglas, who prefers to be called “Gabby,” proved as much at the USA gymnastics national championships in May, winning gold on the uneven bars and getting edged by just two-tenths of a point for the all-around gold by defending champion Jordyn Wieber.

Next comes the 2012 U.S. Olympic trials, Thursday through Sunday in San Jose, where 15 women and 15 men will vie for just five spots each on the London-bound teams. Wieber and Douglas, both 16, appear certain picks. But the stars of the 2008 Beijing Games may be missing.

Johnson, the 2008 gold medalist on beam, retired on the eve of last month’s national championships, unable to fully recover from a catastrophic knee injury.

And Nastia Liukin, 22, who won all-around gold in Beijing, faces long odds after a disappointing performance on beam and a poor showing on her signature event, the uneven bars, at nationals. Liukin’s comeback after a two-year hiatus has been slowed by a shoulder injury. And her chances of making the squad as a specialist, competing in only two of four events, aren’t helped by the Olympics’ reduced roster size, down from six in 2008.

The short shelf life of female gymnasts is among the harsh realities of a beautiful sport.

Injuries are another. And Douglas has had her share. She missed the 2009 national championships because of a broken wrist. In 2010, she struggled with a strained hip flexor and hamstring.

Sacrifice has been part of the journey, too.

It was Douglas’s idea to leave home at 14 for more rigorous training. Her own gym had “a lot of drama,” she confides, full of distracting gossip about boyfriends and breakups.

But it was a hard sell to her close-knit family.

“Emotion-wise, it took a lot,” Douglas says. “I had to convince my mom, and I had to convince my brother and sisters to convince my mom.”

But Johnson’s coach, Liang Chow, took her on. And the parents of a young gymnast at Chow’s, Missy and Travis Parton, took her in, agreeing to rear her in close collaboration with Hawkins.

Johnson, who was attempting a comeback after taking a break from gymnastics that included winning “Dancing with the Stars,” acknowledges a bit of ambivalence over Douglas’s arrival, having never had an elite teammate at her West Des Moines gym.

“It was like sharing my dad for the first time,” Johnson recalls, “and I didn’t know if I wanted a sister.”

But Johnson found she loved being pushed by a younger, more athletic and energetic teammate. And she found she loved mentoring Douglas, giving her advice on the mental demands of international competition.

“I’ve become a proud mama,” Johnson says.

But in January, Douglas abruptly told her mother she wanted to move back to Virginia Beach, a decision that would have thrown her preparation for London in disarray. Hawkins, who describes her daughter as “a wise old soul,” talked it over with her, reminding her that she had worked nearly 10 years to become an Olympian.

“You have this opportunity, and opportunities like this don’t come around very often in a lifetime,” Hawkins recalls saying.

A few days later, Douglas called home to say she was staying.

“I’ve got to do this, Mom!” she said, Hawkins recalls. “I’ve had this dream, and I’m not going to let it pass me by. I’m going to seize it with everything I’ve got.”

Since then, “the Flying Squirrel,” as U.S. national team coordinator Marta Karolyi calls Douglas, has improved at a breathtaking pace.

Her forte is the uneven bars, a traditional weakness of the U.S. women, flying around the bars and delighting in difficult release moves. She’s equally lithe and athletic on the balance beam. And after falling at nationals, which cost her the all-around title, she showed formidable resolve in hopping back on and completing her routine with no trace of nerves.

Pressure, Douglas explains, has never made her “chicken out.” It only drives her to be better.

“Kind of like Superman!’” she says with a laugh.

Douglas’s words tumble out faster than stunts in her floor routine, so eager is she to describe her passion for gymnastics, her love of her two families and her hobbies and heroes-of-the-moment. Nearly every sentence ends with a giggle and implicit exclamation point, whether the topic is playing the piano, doing crochet, Michael Phelps, Usain Bolt or all that is fabulous about Iowa.

“The people are so nice! There’s no traffic! And they have these tractors that go through the cornfields, and the corn shoots out in this big bucket! It’s so cool to watch!” she says in rapid-fire burst.

Iowa is now this Virginian’s home, a necessary and nurturing stop on the road to a dream that ends in London. And that’s where Douglas’s three proud mothers — Natalie Hawkins, Missy Parton and Shawn Johnson — will cheer their daughter on.