(CNN)Riley McCoy took a deep breath. This would be the most time she had spent in daylight in her entire life.
Her rare skin condition keeps her indoors, but she braved the sun to walk at graduation
When she appeared at graduation, her classmates at Dana Hills High School in Dana Point, California, gave her a standing ovation before she was handed her diploma. Riley had made it.
She is known as "the California girl who can't go out in the sun," and it isn't often that Riley gets to be a normal 18-year-old. But this time she insisted by choosing to graduate alongside her peers in an outdoor ceremony.
"I was really excited," Riley told CNN. "Not really nervous, just excited."
Riley was born with xeroderma pigmentosum (XP), a rare skin condition characterized by extreme sensitivity to ultraviolet rays from sunlight, according to the US National Library of Medicine. It affects about one in every 1 million people in the United States and Europe.
If sunlight touches Riley's face or body, it can cause severe sunburns and potentially lethal skin cancer. About 30% percent of people diagnosed with XP also experience neurological degeneration. Riley is one of those cases, but she has never let it keep her from pursuing her dreams.
To walk at graduation, Riley wore latex gloves and a special bubble-front, UV-safe hood with a built-in fan under her blue graduation cap. It was a major upgrade from her usual plastic visor sewn into a hat, which she said fogs up and makes it difficult to see.
A family support group for children with XP purchased the new headgear and plans to share it among the group members.
Riley's mother, Pam McCoy, told CNN she was surprised her daughter wanted to walk with everyone else instead of having a safer, separate graduation indoors at the Southern California school.
"I never thought she'd want to take that kind of risk," McCoy said. "But she really insisted she was going to walk with her friends. There was no convincing her."
To minimize her time outside, Riley was the last to walk at graduation. When students spotted her on the way to the stage in a golf cart, they broke into applause and then a standing ovation, followed by the rest of the crowd.
"We were standing up and the next thing you know all the people around us started standing up too," McCoy said. "Everyone around us was rooting for her and calling her name. There was such a wave of love in the air."
In the commotion, Riley's name was never announced. The long applause seemed to stand in its place.
"Everyone was so happy," Riley said.
Riley says she is both relieved and a little sad that high school is over.
"It's a little bit bittersweet because I'm really sad that I'm leaving everybody," she said.
Riley, whose classmates crowned her homecoming queen last October, said she's grateful for the support she received throughout high school from friends, teachers, staff and her aide.
"They're like a family to me," Riley said.
This fall, Riley said she's excited to be attending Saddleback Community College, where she plans to study theater.
"She just loves theater and entertaining and any kind of singing and acting," McCoy said. "She wants to take a drama class and participate in plays."
For now, she said, she'll likely spend the summer hanging out with her friends and playing with her dog.
Her message to others: "Be yourself."