RIO DE JANEIRO — The text message came from Simone Biles, her younger and tech-savvier teammate: “WYD?’’

“I texted her back saying, ‘What does that mean?’ ’’ said Aly Raisman. “She said, ‘What You Doing? You really are so old.’ ’’

Raisman is 22. Biles, who already is a three-time world gymnastics champion, is 19. That makes Raisman “Grandma Aly’’ to her colleagues, the old lady who has trouble figuring out social media and who turns in early at night.

But when the US women’s gymnastics team takes the floor here Sunday for the Olympic qualifying round, the Needham, Mass., native again will be leading the way as captain as the heavily favored Americans seek their first back-to-back team titles.

“Gabby, I can’t believe we actually did it!’’ Raisman told Gabrielle Douglas, who won the Olympic all-around gold four years ago, after they’d been named to the five-woman team at last month’s trials in San Jose, Calif.

This is a sport that proceeds in fast-forward from one quadrennium to the next, where the generation gap can be as small as three years and where the page turns as soon as the Games end. Nobody from the 2008 squad made the 2012 edition, for example, not even Nastia Liukin or Shawn Johnson, who’d placed 1-2 in the all-around in the Beijing Olympics.

Raisman had nothing more to prove to herself or anyone else after the 2012 London Games. She’d collected the team gold, the individual gold on floor exercise, and the bronze on balance beam, losing the all-around bronze on a tiebreaker. She had relished a prolonged victory lap, appearing on “Dancing with the Stars,’’ chatting with David Letterman, tossing out the first pitch at Fenway Park. Yet Raisman always knew that she wanted to continue competing.

What she wanted first was a break from a sport that had kept her in a leotard since she was 2 years old. The question was, how long could that break be if Raisman wanted to keep up with what national team coordinator Martha Karolyi calls the “up-and-comers’’? One year, she concluded, was the maximum, so she returned to training in September 2013.

“We know very much from the past cycle how it happened with some of the girls who decided too late,’’ said Karolyi, who’ll be retiring after these Games. “For Aly, it was very good that she came back.’’

For her coach Mihai Brestyan, the bigger question was, why? Was Raisman coming back for the gym — or the fame? “Are you going for the Olympics or for advertising and sponsors?’’ he asked her. When she said it was the Olympics, Brestyan said he would give her a year to get herself back into elite condition, then they would talk about the national team.

“It took me three years of being back in the gym to be at the point where I was,’’ Raisman reckoned. “Mentally, it was harder to come back. I wouldn’t have been able to deal with the pressure if I came back last year.’’

Raisman had hoped to be ready for the 2014 national championships, “but it definitely was a lot slower than I thought,’’ she said. She finished third behind Biles and Maggie Nichols at last year’s event and made the team for the global meet in Glasgow, where she had a wobbly performance in qualifying that left her heartbroken, feeling that she’d let her teammates down.

“She looked too hyper and a little bit out of control, which wasn’t usual for her,’’ said Karolyi.

She was much too hard on herself, Raisman concluded, treating every routine as if it were life-and-death. One reason she posed in the nude last year for ESPN The Magazine’s Body Issue was to show girls struggling with body-image issues and eating disorders that a sturdy frame could be attractive. Her message: “It’s OK to be insecure. But it’s not OK to pick yourself apart.’’

It was Raisman’s quest for perfection, her exceptional tolerance for hard work, and her rock-solid dependability that had gotten her on the 2012 Olympic team. Making the next one as a grown woman was an even more formidable challenge. There were days, after seven grinding hours in the gym, when Raisman had to call her father to drive her home from Burlington. But she was determined to press on.

“I want to do it,’’ she said, “to prove to myself that I can do it again.’’

Raisman didn’t want fear of failure to be the reason she didn’t continue on the road to Rio despite the odds. Still, this figured to be an exceptionally difficult team to make. Biles and Douglas had finished 1-2 at the world meet. Nichols was a solid third all-arounder, and Lauren Hernandez, the 16-year-old newbie, was the kind of fresh and frisky face that made even the impassive Karolyi say, “Wow!’’ And the one spot for a specialist was reserved for uneven bars, Raisman’s weakest event.

Before the Pacific Rim Championships in April, the year’s first major competition, Raisman was so nervous that she felt she might throw up.

“Lately, before I go to sleep, I have butterflies in my stomach thinking about the Olympics,’’ she said in June at the Classic, the final tuneup for the national championships.

What Raisman knew from experience was that all of the other contenders were feeling the same way.

So before the trials, she gathered them together and imparted some grandmotherly wisdom.

“I told the girls just to enjoy it, because we’ve been dreaming of this ever since we were little,’’ she said. “There are thousands and thousands, maybe millions of little girls that would die to be here.’’

Still, Raisman found the two nights nerve-racking. Only the unbeatable Biles was automatic. The other four team members were chosen by the selection committee behind closed doors. Raisman’s third-place finish made her all but a certain choice, but what sealed her selection was her proven leadership.

“The other team members are looking up to her,’’ Karolyi said. “Aly is a good role model because she is very dedicated in her training and disciplined and giving 100 percent effort to become a better gymnast.’’

Anything less than that wouldn’t have gotten Raisman a return ticket. When she heard her name announced, she burst into tears both of joy and relief.

“I didn’t cry as much as I did four years ago,’’ she said.

Raisman was still a teenager then. Now she’s the granny who can’t quite figure out the hotel Wi-Fi. But she figures to leave Olympus with at least one gold medal around her neck.

“There were plenty of days when I didn’t feel like I was going to make it, but I just didn’t give up and I kept pushing,’’ she said. “I just didn’t want to look back and have any regrets.’’

John Powers can be reached at john.powers@globe.com.