At 18, she is the youngest member of Jenner's squad, which includes activist Jennifer Finney Boylan, author Kate Bornstein, actress Candis Cayne, and activist Chandi Moore.
In season two, Jenner gathers her friends together for a month-long road trip. For Jenner, it's an opportunity to meet other transgender people and explore life as an activist as she finds her place in the community. But she's not the only one finding herself.
Introduced as a daughter of one of Jenner's longtime friends in the premiere, Giselle knows the reality star through her former assistant Ronda Kamihira. "She was like a second mother to me when I was younger," Giselle tells ETonline about Kamihira, who dated her father.
Despite the connection, it wasn't until Jenner came out on the cover of Vanity Fair that Giselle was aware of the former Olympian. The moment came right as Giselle was finishing her senior year of high school -- and her first year as an openly transgender woman.
"It changed the game," Giselle says of the cover, noticing the impact it had on her fellow students, who had been "receptive but quiet" of her.
Inspired by David Bowie and Lady Gaga, Giselle transitioned between her junior and senior year. The two singers -- Bowie, in particular, who became famous for his androgynous esthetic -- helped her "discover" her gender.
"The moment Caitlyn came out, it was like I was handed this armor," Giselle says. "At that moment, people were asking questions and were really interested."
An aspiring musician, Giselle is also focused on educating the next generation about transgender rights. She cites Jenner's two daughters, Kendall and Kylie, for their public support of their father, who they now call Mad. (It's a combination of Mom and Dad.)
"I'm so proud of them for standing by Caitlyn," she says. "I can spend time on the older generation, but what we really need to make sure is that our next generation really has a hold of this issue and what's really going on."
Though, Giselle is not ignorant of her elders. While filming the show, she grew close to the other women, particularly Bornstein, whom she calls Auntie Kate.
"They're just like the family that you go to when you ask questions," Giselle says. "They bring so much clarity to the table. It's also important for me to know my history and how I am able to walk down the street today."
"It was unreal for me spending a month with them on the bus and absorbing everything I could," she adds.
It was also on the bus where Giselle found a new sense of tranquility. "When you put a bunch of trans people on a bus, the trans is taken away," she says. "All of a sudden, it's just a bunch of beautiful humans."
I Am Cait premieres Sunday, March 6 on E! Watch a preview from the new season below: