"I'm just so game," she said.
Despite her setbacks, though, she has soldiered on, displaying a resilience that her father, whose Navy SEAL days included a stint in Somalia during the "Black Hawk Down" days, notes with pride.
"It's water off a duck's back," her father says. "She doesn't blink."
The upshot of her injury was that she had to wait until the end of other competitions to see how rivals did and whether her ranking was high enough to make the cut — only 36 women and 36 men will compete, and countries can have no more than two of each gender.
After a sleepless night last month in which she kept getting out of bed to check a livestream of a competition, she was in, at least unofficially. Pentathlon officials say that while official notification is still pending, no matter how they crunch the ranking numbers, Stettinius makes the U.S. team.
"The sky is the limit for her in London," says Rob Stull, managing director of USA Pentathlon, himself a former Olympic pentathlete and fencer. Stull said that while Stettinius' international ranking may be toward the bottom of the 36 Olympic competitors, each event begins with a clean slate, with competitors rising and falling with each sport.
"It makes the sport particularly interesting," William Stettinius said. "You can't predict where the pack will end up."
All sorts of wild cards enter into the competition. During fencing, each competitor has to duel every other one. Horses are assigned by random, with entrants getting just 20 minutes to warm the animal up before starting the obstacle course.
While the event used to sprawl over four or five days, it was compressed into a single day starting in 1996. Women competed for the first time in the 2000 Games. And, after the 2008 Olympics, the running and shooting components were mashed into one event, with athletes firing at targets and running one kilometer, three times. And the guns now shoot lasers rather than bullets or pellets.
These days, Stettinius' time is filled with practices and competitions — on a recent weekend, she had both a swim meet at the Meadowbook pool in Baltimore and a fencing match in Washington. Soon, she'll head to the U.S. Olympic Training Center in Colorado.
Her supporters are thrilled to see her heading to London.
"I think this is a unique opportunity for her, given her unique athleticism," said Davies, her riding coach. "It would be a waste to just ride horses."
Stettinius has been training for pentathlon full-time since graduating from McDaniel. She had joined the school's swim team to help with what she considers the weakest of the five events, and McDaniel's swim coach, Jeff Hiestand, still works with her.
He is among the coaches she hopes to send to London to see the fruits of what in most of their cases has been free labor. Her running coach, for example, is the father of a girl she had coached in riding; her massage therapist saw her Facebook page and volunteered her services.
She's trying to raise $60,000 through fundraising events such as a toga party on June 24 at the Manor Tavern in Monkton.
"You know how they say it takes a village to raise a child?" says Avis Stettinius, who is stitching up a toga for her Olympian to wear that night. "It takes a village to send her to the Olympics."