WASHINGTON — When people approach the teenage subjects of the documentary "Step," the girls know what's coming.

"We expect all of them to cry," said Tayla Solomon. "Most people do."

A year ago, Solomon, Blessin Giraldo and Cori Grainger were fairly typical kids. They'd just graduated from the Baltimore Leadership School for Young Women and were getting ready to start college.

Now, Michelle Obama is tweeting about how phenomenal they are, and they're scheduled for interviews on all the morning talk shows. This isn't what they expected when filmmaker Amanda Lipitz asked to chronicle their senior year on the school's step team. They thought the movie would be a small thing — a time capsule for a few people.

But then "Step" was selected for this year's Sundance Film Festival.

"I didn't even know what Sundance was, so I had to do my research," Grainger said during a recent visit to the District of Columbia. "Then we went to the premiere and we won an award. I think that's when it clicked for a lot of us."

Suddenly, "Step" felt less like a documentary and more like a phenomenon. Impressively shot with captivating subjects, the film, which came out Friday, is an uplifting tear-jerker, set in a city still grappling with Freddie Gray's death at the hands of Baltimore police. "Step" is, in part, about the team's quest to win a big competition, but it also covers much more: how difficult it can be to escape from poverty; how important advocates are; and, of course, the tribulations of being a teenager.

The response to the film has been overwhelming. After screenings, viewers feel compelled to offer the girls pep talks or relay how they overcame their own obstacles.

The power of the movie lies in the girls' openness about their complicated emotions and fears — we see them crying because there isn't food in the house or the electricity has been shut off. It can't be easy to let the world see you at your most vulnerable, but the trio seems at peace with what's on screen.

"There are some parts of our personal lives that need to be shown," Solomon said, "not because we want it to be shown, but because a lot of people can relate to it."

Added Grainger: "Sometimes it's a little uncomfortable to watch, because it's our stories and our struggles. But at the same time, at the end, it's our triumphs — our making it out of whatever situation we were feeling stuck in at the time."

The three young women, all 18, were part of the first class at BLSYW, a school that aims to send every student to college. Two years in, the charter school has succeeded, and the girls are on their way to being the first in their families to get a bachelor's degree. Giraldo just finished her first year at Coppin State University, Grainger is at Johns Hopkins and Solomon attends Alabama A&M.

The intimacy that audiences are finding so moving is the result of a close connection behind the scenes. Lipitz has known the girls since they were 11, when they started at BLSYW in sixth grade. A Tony-winning Broadway producer, she has also made about 30 short films about young women who are the first in their families to go to college. She started shooting at BLSYW as a favor to her mother, who founded the school.

When Lipitz met Giraldo, the two immediately clicked — the young girl's dream is to one day be on Broadway. And then, after Giraldo launched the school's step team, she insisted that Lipitz film the group.

The director wasn't that familiar with step, but as soon as she saw a practice she understood the power of it. It felt like a musical. Watching the performance reminded her of "the way you feel when a character expresses themselves through song," she said. "That's what they were doing with step."

You can see what she's talking about in the movie. The fiery Giraldo channels her emotions into her athletic routines, and Grainger, who's bookish and shy, uses step as a release. It's the time when she can be as bombastic as she could ever want.

Lipitz filmed occasionally during the girls' early high school years, teaching herself how to shoot dance routines while the team got increasingly comfortable with her. Then she spent their senior year getting as much footage as she could.

That included time at home with families, on dates, during church services and over many meetings with the school's effervescent but demanding college counselor, Paula Dofat, who also bared her soul. In one of the movie's most poignant scenes, she breaks down to a college-admissions officer, explaining that if the school doesn't give Giraldo a chance, the consequences could be dire. "This is so unprofessional," she admits through tears.

At the time, she had forgotten the cameras were rolling. As soon as she remembered, she requested that Lipitz ditch the footage. She's not a crier, she insists.

"Of course, there goes Amanda finding my one soft moment of the year where I'm bawling my eyes out," she said during a recent interview.

But now she's glad the scene made it in.

The scene takes her back to the powerful feelings rushing through her: how afraid she was to let Giraldo down; how letting Giraldo down meant failing not just the other girls in the school but also — "and this sounds really grandiose" — the larger community.

On the press tour with the girls, she's still holding them to high standards. Part of her job now is to keep them grounded amid all the publicity and accolades, and experiences like meeting musician John Legend backstage during the Park City, Utah, women's march. Part of that is taking time every day to talk about what they're grateful for — and not just the superficial stuff.

"You have to really think about it," Doufat insisted. "Staying in a nice hotel doesn't make the cut."

The girls are clearly grateful for the opportunity to connect with people across the country, even though sometimes they have to educate the audiences about what their urban upbringing was really like.

The way Giraldo sees it, "Step" gives viewers an excuse to be as vulnerable as the characters they've gotten to know. People who might otherwise be too proud find themselves making surprising admissions about all they've been through.

"We don't go to Q&As that are full of girls or boys like us," Giraldo said. "It's a different crowd in every city and to see people all cry and say they relate to your situation — I feel like we're breaking down barriers."