The 17-year-old swimmer said Thursday she was affected by the cinema shootings in the Denver suburb of Aurora, where she attends high school and trains.
"Every single race I'm going to have that Colorado incident back on my mind," she said. "It's such a terrible thing and I'm so shaken by it. They're in my thoughts this entire process."
Franklin, who lives in Centennial, Colo., said she and her parents didn't know any of the 12 shooting victims or the 58 others who were injured.
"But Aurora and Colorado in general is such a close state that when something like that happens we're all affected by it, no matter who it is," she said, adding that she had never been to the cinema where the shootings took place. "It's hitting very close to home."
Franklin and the rest of the U.S. swimming team was training in France when she first heard about the shootings through Twitter. Because of the time difference, she had to wait several hours to find out if any of her friends had attended the midnight showing of the Batman movie.
One of them did but "thankfully he was not at that theatre," she said.
Franklin will have to clear her mind of the tragedy while she competes in seven events at her first Olympics. She opens her program Saturday, when she's expected to swim a leg of the 4x100-meter freestyle relay on opening night at the Aquatics Centre.
No less an expert than 14-time Olympic gold medallist Michael Phelps said Franklin's biggest challenge will be harnessing her boundless energy over the eight-day meet, but Franklin believes last month's ultra-competitive U.S. trials gave her valuable experience.
"I know that I've done this many events before and I'm ready to add in relays, but relays are my favourite part and I think those are going to give me energy," she said. "I know that it's going to be tough, but like Michael said, it's all mental and I think that I'm prepared to do it."
Phelps even told Franklin to ask, phone or text him if she needs anything.
"She hasn't," he said. "I offered."
As mature as the bubbly teen is, she was thrilled that her parents arrived on Thursday to watch their only child compete.
"I'm so happy to know that they're here, but apparently my dad is calling everyone 'mate,'" she said with a smile. "I'm like, 'Wrong country, Dad,' but as long as he doesn't tell anyone he's related to me, it's fine."
Franklin's enthusiasm extends to her digs at the athletes village.
"The apartments are so nice. We have these little, like, London bedspreads that we're able to take home. They're so cute," she said.
"We have little living rooms — they have blue couches and pink pillows. Everything is so colorful. They planted, like, 18,000 trees in the village, so to have that, it's so beautiful and just the village itself is gorgeous."
Her first trip to England, which has included seeing the Tower of London and Tower Bridge, has exceeded Franklin's expectations.
"It's so beautiful and so grand," she said.
Her compliments extend to the Olympic pool and its sloping roof, which resembles the belly of a grey whale.
"It hasn't really intimidated me," she said. "I feel really relaxed and really comfortable in that pool."