The senior at Dana Hills High School in Dana Point, who is battling a rare genetic disease, was named homecoming queen Friday night during halftime of the school's football game.
"I'm very blessed to have such amazing people in my life," Riley said while wearing her crown and holding a bouquet of roses. "I'm super happy and thankful and blessed."
Riley suffers from xeroderma pigmentosum, or XP. She has never let it stop her, but it does keep her from going outside when the sun is shining.
"Xeroderma pigmentosum, at six days old, she had very serious burns from just a few minutes in the shade," explained Pam McCoy, Riley's mother.
XP causes extreme sensitivity to the sun's ultraviolet rays; even a small exposure can cause severe sunburns like Riley suffered as a baby. People diagnosed with XP are 1,000 times more likely to be diagnosed with skin cancer than the average person.
Riley can't go out in the sun, and kids like her are affectionately called "moon children." If she has to go into the sun, she wears gloves and covers her head with a special protective shield.
In some cases like Riley's, it also causes progressive neurodegeneration. But none of that matters to her friends.
"She just makes everything light up, she's the light in the room, she's so positive," said Katie Swanson, a senior and fellow member of the Dana Hills' homecoming court.
Riley's positive attitude has been returned to her by the entire student body. At a pep rally on Friday, the crowd chanted her name as she was introduced.
"I feel like I'm in a fairytale, like a movie," said Pam McCoy. "She always wanted high school to be like 'High School Musical.'"
Riley (who voted for someone else to become queen) walked out to the 50-yard-line at halftime Friday evening, wearing a blue gown and escorted by her father.
The crowd erupted in cheers when she was announced as queen of the homecoming court.