Andrea Castilla was swaying among the crowd of roughly 22,000 concert-goers on Sunday night, holding hands with her sister and listening to Jason Aldean when gunfire erupted.
Castilla, a Huntington Beach resident who was in Las Vegas celebrating her 28th birthday at the three-day Route 91 Harvest country music festival, was fatally wounded during a gunman's barrage of bullets that began shortly after 10 p.m.
Castilla's boyfriend and sister and her sister's fiance picked her up and carried her from the outdoor venue, her aunt Marina Parker wrote on a GoFundMe page to raise money for Castilla's funeral.
"They continued to shield her as bullets rang out around them," Parker wrote.
Eventually, the group reached a highway and flagged down a passing motorist, who took them to a hospital in the back of his truck.
Castilla's family sat in the hospital emergency room for seven hours waiting for an update. Hospital staff members told them Castilla was in surgery. However, they eventually realized that in the chaos they had confused her with another patient, Parker wrote.
In fact, Castilla had died almost immediately after reaching the hospital.
As of Wednesday afternoon, more than 1,000 people had donated nearly $54,000 toward her funeral.
In all, the massacre claimed 59 lives, including the gunman, Stephen Paddock, and left hundreds wounded, according to the city of Las Vegas. Authorities have called the tragedy the deadliest mass shooting in modern American history.
Castilla, who graduated from Estancia High School in Costa Mesa in 2007, is remembered among her friends as a compassionate, artistic, humble and beautiful woman who was ripped from them too soon.
Jose Franco, who attended Estancia and TeWinkle Middle School with Castilla, said he hasn't been able to come to terms with the death of his energetic former classmate.
"I still can't believe that happened to her," Franco said. "It's still very stunning and shocking. … She did not deserve that."
Carol Avella, who attended Estancia with Castilla and played alongside her on the school's soccer team, said the two became friends in sixth grade. Avella couldn't recall a moment when Castilla wasn't happy.
During a soccer match in their freshman year, the Estancia team was soundly defeated by rival Costa Mesa High, but the loss didn't faze Castilla, Avella said.
"Everyone on our team was mad," she recalled. "I remember telling Andrea she could have been a better defense and all she did was laugh at me. She said, 'Carol, it's just a game,' and smiled at me. While the rest of the team was upset, she was cheering us up."
Rebecca Lau, who also attended Estancia with Castilla, said they competed on the swim team together.
Castilla's energy was boundless, and good feelings were never far away when she was around, Lau said.
"That's what I think she delivered to everybody," she said.
Castilla's mother died of cancer when Castilla was a teenager, and she and her three siblings were raised by their father. For a few months, Lau said, Castilla lived with her and they bonded like sisters.
Lau said Castilla was a talented artist who made her a friendship card. The card, which she has kept for more than a decade, shows two butterflies frolicking near the shade of a palm tree. It reads, "Becky, when you need a friend I'm here 4 you!"
Jazmine Rayner-Cullum, who was Castilla's close friend when the pair attended Estancia, said Castilla's artistic talents included making her own dress for the senior prom.
"No matter how hard life could be, she was always happy and had such a beautiful smile," Rayner-Cullum said. "She is a beautiful soul. … I am blessed to have her as my best friend and sister at heart."
Organizers of the Estancia class of 2007 10-year reunion, which is scheduled for November, said they're discussing incorporating a memorial for Castilla or dedicating a scholarship in her honor.
According to Castilla's Facebook page, she attended Cypress College and worked the past two years at Sephora in Huntington Beach as a beauty advisor. Her family told People.com that she was inspired by her mother's illness to help other cancer patients look beautiful.
"All of us at Sephora are shocked and deeply saddened by the loss of Andrea Castilla," Calvin McDonald, chief executive of Sephora Americas, said in a statement. "She was a beloved employee, known to her colleagues in Huntington Beach for her vibrancy, liveliness, caring and consideration of others.
"She will be greatly missed. Our thoughts are with Andrea's family, and we send our condolences to the loved ones of all of the victims in this terrible, senseless tragedy."
Castilla's older brother, Adam, with whom she shared a birthday, wrote in a Facebook post Wednesday that she was the greatest gift life had ever given him.
"I can't even close my eyes without picturing the joy you brought to me and this world," he wrote. "Never have I had something so precious ripped from my life. I am completely shattered."
Her father, Gus, shared a photo of him and Castilla, his arm wrapped around her shoulders as they smiled.
In a Facebook post, he wrote: "As the sun shines through my window and I hear the birds sing, I wait quietly for you, for that small voice that says, 'Dad, I'm with you. I never left you.' "
Staff writer Ben Brazil contributed to this report.