It was getting close to 6 p.m. on Thursday night, which meant it was getting close to naptime for Reed Kessler, but when the pink box plopped down on her table at a pizza place, the 18-year-old, mouth agape, neck craned forward, had one question.

“Oh my god,” Kessler gasped. “Are those red velvet?”

The crowd of 11 girls sitting at her table nodded in shared wonder. The youngest Olympic show jumper in U.S. history, Kessler is a preternatural talent atop a horse and the champion of a new generation of equestrian talents. She’s also very much a teenager, prone to do things like quote lines from the TV show “Psych,” grouse about sleep deprivation and, on this day, freak out over Georgetown Cupcake.

Kessler, one of the Washington International Horse Show’s biggest stars this week, won the $100,000 President’s Cup Grand Prix in a jump-off Saturday night at Verizon Center. She is in most ways just a normal college-aged girl. But to see how some of her closest admirers — in this case, a pack of the show’s 15-, 16- and 17-year-old volunteers — stare at her as they sit in reverent silence is to realize the Lexington, Ky., native is not exactly one of them.

The daughter of two longtime riders, Kessler was “always a young rider moving up, someone to watch, that kind of thing,” she said. At age 13, Kessler’s coach had told her to start preparing for the 2012 Summer Olympics. She laughed off the suggestion. She was only at the junior level then, and she’d never even competed against riders her parents’ age.

When she arrived in Wellington, Fla., for March’s national show jumping championships, little had changed. She’d come for the experience, and little else.

“I went from, like, pre-algebra,” Kessler said, “to, like, nuclear fission.”

Everyone noticed. Despite becoming eligible for senior-level competition only a month earlier, Kessler rode her mount Cylana to a first-place appearance and a spot on Team USA.

“Nothing seems to flap her,” said Robert Ridland, the team’s future chef d’equipe, or manager. “She’s pretty much unflappable, as the results showed.”

Kessler just missed the cut for the final rounds in London, finishing 47th overall in the individual competition. And unlike in the previous two Olympics, there would be no gold for Team USA, which tied for sixth.

Kessler found ways to make up for it. She met gymnast Aly Raisman. She tried on bag after bag of free gear. Perhaps the only disappointment, she explained Thursday to a chorus of dismayed groans, was that she didn’t get to meet swimmer Ryan Lochte.

Said Elizabeth Kruse, 15, of McLean: “It’s kind of cool to have her be someone close to my age.”

With her final goodbyes made, Kessler turned from the table of tweeting teenagers and half-eaten pizza and started back to Verizon Center. At least, that was the plan. Kessler stumbled awkwardly on the steps of the storefront before catching herself just in time. She looked back to see if anyone had noticed.

This was, after all, an 18-year-old girl.