When 18-year-old Caroline Harvey showed up to the U.S. women's national team selection camp in June, she was the youngest player there. And she had no idea what her next few months would look like.

If Harvey didn't make the national hockey team, she was set to enroll for her freshman year at the University of Wisconsin the following week. She already had an English 100 class picked out.

And if she made the roster? Harvey would defer, joining her much older teammates for the 2021 IIHF Women's World Championship in Calgary, a months-long residency program in Minnesota, and ultimately the 2022 Olympic Games in Beijing.

"It was a little nerve-racking," Harvey said, "not knowing how things would play out."

Harvey, a defenseman who grew up in Massachusetts, stood out during the tryouts. She was too good not to put on the roster.

"She's so skilled," veteran U.S. defenseman Megan Keller said. "I just enjoy watching her in practice. She's so fun to watch, especially at her age, the things she can do with the puck, her skating ability. She's a little Energizer bunny out there too."

Harvey will join the Badgers next spring. By the time she gets there, she might be a household name.

U.S. women's hockey sits atop the international throne right now. The team got over its Olympic hump by beating rival Canada in 2018 for its first Olympic gold medal in 20 years. Before they get the chance to defend in Beijing, the women will compete in the world championship, which begins Friday and runs through Aug. 31. The Americans have won the past five tournaments, and eight of the past nine.

But the stop-and-go nature of the pandemic has been challenging -- a cruel gambit of cancellations, decreased ice time and decreased visibility. When the U.S. opens worlds with a game against Switzerland on Friday, it will have been 859 days since the team last played in a major international tournament.

In that time, there has been significant turnover on the roster. Captain Meghan Duggan, twins Jocelyne Lamoureux-Davidson and Monique Lamoureux-Morando (who scored the winning and tying goals in the 2018 Olympic gold-medal game) and 15-year veteran Kacey Bellamy all have hung up their skates in the past year.

"We've had a lot of veterans, and girls that have made this program what it is, retire," Keller said. "Especially in these past two years with worlds being canceled twice, you have more new faces, new teammates and some new blood mixed in. It's exciting to get this new group together finally. I think we have a really good mix."

Enter Harvey, who ushers in a youth movement. She's one of four Americans born in the 2000s playing at the world championship -- joining forwards Britta Curl, Lacey Eden and Abbey Murphy -- and one of seven rookies overall.

As Keller said, "One of the coolest things about being on the national team is being able to play with your role models," and Harvey already is experiencing that. Growing up, Harvey said she always looked up to Bellamy.

"We were at a couple camps together before she retired; I got to learn a lot from her," Harvey said. "It was cool to hear what she had to say, but also just see the way she handled herself. She was really fun to be around, but when it was time to be serious, when we were practicing, or even warming up, or cooling down, you could see how locked in she was. She was funny, and let that side of herself out when it was appropriate, but she changed and could be so locked in when she needed to be."

Harvey will get to play with some players she looked up to -- like Hilary Knight, who enrolled at Wisconsin 14 years before Harvey -- but she's trying to soak up as much wisdom from as many sources as she can.

For her five-day quarantine in Calgary, Harvey brought along the Lamoureux twins' book, "Dare to Make History."

She also has some experience with her new teammates, though not a typical relationship. One of the Americans' alternate captains, Brianna Decker, was an assistant coach with the U-18 team Harvey played on. And Keller's roommate at Boston College was one of Harvey's coaches in club hockey, who revealed that Harvey is rarely called Caroline by anyone.

"When I was young, my sister couldn't pronounce Caroline, so she called me KK instead," Harvey said. "We were really young, but it stuck."

Harvey hasn't found it too hard to mesh with the senior team. She and Keller have been plotting a TikTok dance for their teammates. Harvey has similar interests as her older teammates, including Netflix shows such as "Outer Banks" and "All-American." Music in the locker room is a different story.

"When the music gets going, we're constantly asking, 'OK, who knows this one,' whether it's a new one or old one," Keller said.

Adds Harvey: "I know of the songs from my parents. They're not my parents' age, but I know some of the songs, just in a different way."

For Harvey, it has been a transition to level up with the top competition.

"When you're invited to a national team camp, it's the best of the best," she said. "It's pretty intimidating to see who you are going up against. I was really nervous at first, I was just getting used to these girls, and the pace. It was definitely a scary thing at first to be the youngest and be here, but now I'm feeling comfortable around them."

Harvey has been comfortable around the rink her entire life. Her dad used to take her to her older brother's practices, and would turn the stroller around to let Harvey watch. By 3, she was on skates. Aside from a brief cameo at goalie, Harvey has played defense her entire life.

"I like being able to see the whole ice, and seeing plays develop," she said. "I also like being offensive at times, and having that aspect to my game."

Keller said besides Harvey's skill, the best aspects of her game are her speed and offensive knack, "but she's not afraid to be physical."

Harvey is off to a good start. In the first exhibition against Russia this week, Harvey took a penalty. Shortly after, she collected a pass from Knight, took a shot, then scored on her own rebound to give the U.S. a 3-0 lead. It fits into the advice she received from Decker: Play free. Don't think too much. Let your instincts take over.

Harvey knew she wanted to play at this stage eventually. She never thought it would come this soon.

"I didn't really think much of it a year ago," she said. "Looking at it now, thinking about the position I'm in, it's crazy how things happen sometimes."