Proposal Awaited Calif. Woman Killed on Birthday Trip to Vegas: ‘We Talked About Spending the Rest of Our Lives Together’

Andrea Castilla’s week-long trip with her boyfriend out to Las Vegas to visit her sister was a 28th birthday present to herself.

But there was one thing still ahead that Castilla didn’t know about when a gunman’s bullet struck her in the head Sunday night at an outdoor concert in the nation’s deadliest mass shooting: Her boyfriend was planning to propose marriage.

“He told me after she had passed,” Andrea’s sister, Athena, tells PEOPLE of the conversation with Derek Miller, Andrea’s boyfriend of seven months who lived with Andrea in Huntington Beach, California.

“They were planning on staying on until Thursday in our guest room,” says Athena, 26. “He told me, ‘I was planning on asking her this weekend with you guys. … We talked about spending the rest of our lives together.’ ”

“They had promise rings, and they always talked about it,” adds Andrea’s brother Adam, 33. “Derek had asked my dad’s permission. He wanted to start a family with her.”

Andrea, 28, was a funny, creative and photogenic makeup artist inspired by her mother’s cancer to help other cancer patients look and feel beautiful, her siblings say.

Two weeks before she died, Andrea bought three-day passes to the Route 91 Harvest country music festival for her and her boyfriend, although her sister and her sister’s fiancé had planned for months to attend the event. Her birthday was Friday.

“When she realized fell on her birthday weekend, she was like, ‘Oh no, I’m coming!’ ” Athena says. “She told me, ‘I love country … We’re going to have a great time, so excited to see you!’ ”

Despite living far apart, the sisters — in a family with two boys and two girls — were virtually inseparable. “I love waking up in the morning with texts from her,” Athena says. “’Good morning sis, are you awake, can you talk?’ ”

She adds: “We always talked when we were together about what we were going to do next.”

Recently it was a camping trip to Lake Tahoe, where they visited with Miller’s family.

“She loved hiking,” Adam says. “She loved being healthy. She drank green tea. She wanted to live a long life, you could tell. Anything that had to do with being in good shape, she was passionate about — not just looking good, but feeling good.”

As a high school swimmer, Andrea “loved competition,” Adam says. “She beat all the girls, so she would race all the boys, and she would beat them too.” Later she pursued a professional interest in dentistry, but she felt her interest shift and went to work instead for the cosmetics company Sephora, earning her certification as a beautician.

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“She was so focused,” Adam says. “When she told me what she wanted to do, it was like a light lit up. She wanted to do it because it helped so many other people.”

Their mother, who died in 2003, had been diagnosed with breast cancer, and chemotherapy treatments caused her to lose her hair. But Andrea focused their mother on the beauty that remained, Athena says.

“She wanted to make everybody look beautiful and feel beautiful,” Adam says. Over breakfast with her brother in California before Andrea left for the Las Vegas trip, “that was the last thing she told me, actually,” he says.

“She was a true dreamer,” he says. “Anytime she would look at anything, it was always positive. Anything and everything, she would always turn it into a positive.”

Andrea and her boyfriend attended the Sunday concert with Athena and Athena’s fiancé. Just as a performance by Jason Aldean began, Andrea posted a live video from the event, “and everybody looked so happy,” Adam says.

Then Andrea was hit during the initial volley of gunfire that began shortly after 10 p.m., which authorities traced to the 32nd floor of the nearby Mandalay Bay hotel before closing in on the shooter, 64-year-old Stephen Paddock, who took his own life.

Fifty-eight people, plus the shooter, were killed, and more than 500 others were injured in what is now the nation’s deadliest mass shooting by a single gunman.

“We just weren’t sure what it was at first,” Athena says. “Then everyone started running.”

“Next thing you know,” she says, “ on the floor.”

“My fiancé and I covered her body to keep people from stepping on her,” Athena says. “Her whole hair was drenched in blood. The gunshots kept going and going. We were just praying we were going to make it.”

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Once the shooting stopped, strangers approached them to help get Andrea to a hospital, and with no time to wait for an ambulance, she was loaded onto a metal gate and placed in the back of a truck.

“There were people on the streets trying to take people,” Athena says. “I was holding onto her head and trying to keep her from losing so much blood, talking to her, kissing her, telling her she was going to make it.”

“She was trying to breathe. She was struggling, her eyes were closed. … She was just struggling really bad,” Athena says. “We all did our best to help her get through it. We did the best we could.”

At the hospital Andrea was swiftly whisked away. The next morning, her gathered family members were told she had died soon after arriving.

“They wanted to have kids right away,” Athena says of her sister and her sister’s boyfriend, who was not injured in the shooting. The revelation of his planned proposal made Athena “so happy to hear what happiness would have had if this tragic weekend didn’t happen — what was ahead of her in her life, what a beautiful life she was going to have with him.”

“They truly adored each other,” Adam says. “I’d never seen her that happy.”

Although Andrea had an inkling that a proposal was coming, “she didn’t know exactly when he was going to do it,” her sister says. “I think he was planning to do it because they were both going to be out here and having such a good time together.”

“She was just so excited about life.”

Now, with Andrea gone, “any time I close my eyes, and I picture her, it’s always her smile,” says Adam. “It’s never anything else.”

How to Help

Friends and family are asked to report missing people believed to be connected to the shooting using the hotline 1-800-536-9488.

Anyone with photo or video evidence of the shooting is asked to call 1-800-CALL-FBI.

A victims’ fund has been started on GoFundMe by Steve Sisolak, the Clark County, Nevada, commission chair. Other groups providing relief include the local chapter of the American Red Cross and the National Compassion Fund.