In gymnastics, as in so many things in life, good timing is essential. And in Grace McCallum’s case, it appeared the calendar might not work in her favor.

The Isanti, Minn., gymnast turned 16 last year, which meant she had to move up to senior-level competition for the 2018 season. But her birthday wasn’t until October, leaving her on the very young end of the U.S. elite talent pool. That felt like an unfortunate quirk of fate to coach Sarah Jantzi — until changing circumstances paved the way for McCallum to build her international resume.

“As a young, first-year senior, she was on the bubble to make some of the big meets,” said Jantzi, who coaches at Twin City Twisters in Champlin. “But there were some top seniors who chose not to compete. That opened the door for Grace. And when people see how much progress she’s made in the past year, I think the world will start to notice her.”

That could happen as early as this week, when McCallum will be among the medal contenders in the all-around at the U.S. Gymnastics Championships in Kansas City, Mo. With only one year to go before the 2020 Tokyo Olympics, she already has proved herself on the international stage, despite her youth.

Jantzi said the turmoil at USA Gymnastics — still dealing with the fallout from the Larry Nassar sexual-abuse scandal — caused some gymnasts to pull back from global competition last year as they waited for the organization to regroup. McCallum felt ready and willing to step in. In her first international meet as a member of the U.S. senior team, she won the all-around at the Pacific Rim Championships and helped the Americans to team gold.

As it turned out, that late birthday couldn’t have come at a better time. McCallum turned 16 on Oct. 30 in Doha, Qatar, standing on top of a podium as part of the U.S. group that won the gold medal in the team competition at the world championships.

“Everything was so new last year,” McCallum said. “Doing all those things for the first time, I wanted to do well for my country and enjoy the experience. But it really boosted my confidence, too.

“Before then, I never really thought of myself as being one of the better [gymnasts]. And then, I was like, ‘You actually are up there with them.’ You know you actually have a chance, and that’s very motivational.”

Olympic all-around gold medalist Simone Biles is a heavy favorite to win her sixth U.S. all-around title this weekend. McCallum is part of a deep group of women contending for the other four spots on the U.S. team for October’s world championships in Stuttgart, Germany.

She has performed well in the all-around competition at top-tier meets this season, finishing second at the American Cup and third at the U.S. Classic. With a new floor exercise routine she described as “more mature and grown-up,” McCallum is polishing her performance skills, something that does not come easily to her.

In contrast to gymnasts who seem born for the spotlight — think Biles, Shawn Johnson or Mary Lou Retton — McCallum barely spoke when she came to Twin City Twisters four years ago. She preferred to work on her skills by herself, attracting as little attention as possible.

“Grace is competitive, but she’s super quiet about it,” Jantzi said. “She’s a very, very shy kid. We’re trying to get her to be more outgoing, and she’s gotten 100 times better. But she just isn’t that bubbly, look-at-me personality, and I think that’s why she doesn’t get recognized as much.”

When other gymnasts were hurt or sat out with USA Gymnastics in disarray, McCallum leapt at the opportunity to get substantial international experience. Following her performance at the Pacific Rim meet, she competed at the Senior Pan American Championships, again winning all-around and team gold. She capped her memorable year by hitting all her routines at the world championships, then going out for a birthday dinner with parents Edward and Sandy.

All that seasoning, McCallum said, has left her confident and well-prepared for what lies ahead. Jantzi is slowly adding upgrades to her routines, and performing her floor exercise — set to the crowd-pleasing “Hava Nagila” — is becoming more comfortable.

With the world championships two months away and the Olympics drawing closer, it now seems McCallum’s timing is just right.

“It was really a surprise to make the world championships team last year,” she said. “I mean, at the beginning of the year, I hadn’t even had an international assignment.

“There will be more pressure with the Olympics next year. I have to think, ‘I’m just going to do my gymnastics and have fun with it,’ and not overthink anything. I’m really excited.’’