RIO DE JANEIRO—Katie Ledecky is about to hit the big time.

Arguably she is already the best swimmer on the planet but these Olympic Games are expected to launch Ledecky into Michael Phelps territory: a face recognized on every street in America.

Her entire world is in the process of being turned upside down. "I'm not thinking about that," she told The Daily Beast, smiling as she suppressed a laugh. "I've got a busy week ahead, and that's all I'm thinking about."

She certainly does. She won silver on Saturday night in the 4 x 100m freestyle relay and is expected to add at least three golds in the coming days.

Talking to the head coach of the U.S. women’s swim team, it’s obvious that he is in awe of the youngest member of his squad. “She's not superwoman but she is pretty darn super,” said David Marsh after her first appearance at Rio 2016.

Ledecky, 19, hasn’t even started at college yet—she will head to Stanford next year—and yet this is her second Olympics. She stunned the swimming world with her first Olympic gold medal in London at the age of 15 in her first ever international meet.

Four years later, this blonde athlete from Washington D.C. is set to become the face of Team USA.

The coach unexpectedly selected her as part of the U.S. team for the 100m freestyle relay on Saturday even though she only came 7th at that distance in the U.S. trials. Ledecky already holds world records in the 400m, 800m and 1500m but she doesn’t consider herself a sprinter.

Thrown into the first relay at Rio 2016 in an unfavored event, she did what you’d expect any superwoman to do—she blasted away the rest of the team with a split time of 52.6 seconds—more than a second quicker than her previous best time this year.

When the pressure was on, she found a new gear.

“I would say I was very pleased, not surprised,” said Marsh. “She's Katie Ledecky! I don't think she knows her top limit yet."

By the evening, she had been selected to swim the team’s anchor leg and she brought the girls home in second place behind an Australia team that was breaking the world record.

She said afterwards that this was the first big 100m relay she’d raced since high school.

Asked if there was more pressure competing in a team, she paused to think.

"Um, No. I don't think so," she said, her voice cracking slightly. "It is more pressure in that you want to compete for your team. We're All In This Together... Abby [Weitzeil] had a little High School Musical in her head earlier that probably rubbed off on me a bit, but we wanted to fight for Team USA."

While Phelps was the flag-bearer at what must be his final Olympic Games at the age of 31, Marsh said Ledecky was ready to lead this swim team even though she is still just a teenager.

“I think she already does in a lot of ways; she doesn't use too many words but she is definitely a leader,” he said. “One, she's always in the water, you see the sets she's doing and you also just respect how she goes about her business… You kinda slide over to that side of the pool so you can watch what she's doing because it's kind of out of the ordinary, off the Earth kind of stuff.

“Last time she was not a leader because she was just the new kid and we were all just admiring her times in practice going ‘Holy mackerel, she might pull the biggest upset in London’ and she did…

While Phelps is a spectacular freak of nature with an arm span of 6ft7, short legs and an elongated, powerful torso, Ledecky looks almost like an ordinary American teenager. OK, she is over 6ft tall, but she wouldn’t have stood out on a tour of the Stanford campus.

She certainly will when she starts at the school after these Olympic Games, as she will have become one of the most recognizable athletes in America.

Waiting for her at Stanford, will be Lia Neal, a 21-year-old swimmer from Brooklyn who shared a room with Ledecky on her first Team USA training camp before London 2012.

“That was the first time I really got to know her and I just loved her,” Neal told The Daily Beast. “We got along so well, she's one of the most down to Earth —but also extraordinary people—you'll meet.”

“We were in the elevator the other day and someone who didn’t recognize her said, ‘What do you swim?—she's like ‘freestyle’ and that’s it.”

Tanja Kylliainen, who was born just down the I-95 in Baltimore, said it was incredible to watch Ledecky’s rise.

“She’s a phenom,” she said. “It’s so much fun to watch.”

Kylliainen, 23, is still at school in the U.S. but she represents Finland so has something of an outsider’s perspective.

She isn’t sure Ledecky can quite emulate Phelps. “Maybe over the next few years but it’s difficult to say because he’s the greatest of all time,” she said. “Personality-wise it’ll take a little more experience to become a leader but she has the potential.”

Marsh agrees that out of the pool you could still occasionally mistake her for a carefree kid. “You catch her giggling, you catch her laughing. She has a completely contagious laugh if you get her in that mode,” he said.

She should have plenty to laugh about here in Rio where she is expected to grab a haul of golds to add to her first from London.

At the World Championships last year, she did something that has never been done before. She won gold in the 200m, the 400m, the 800m and the 1500m. The feat has become known as “the Ledecky slam.

Phelps has 18 gold medals—more than twice as many as any other human in sporting history—but he better watch out, Ledecky is hot on his heels.