Katelynn Smoot was just moments away from welcoming her son, William, into the world. Life already felt picture-perfect — she and her husband, Tyler, were raising their 18-month-old daughter, Lilah, in North Carolina, cherishing the little moments of her singing and dancing along to The Wiggles or Taylor Swift. Growing their family felt like a dream unfolding.

But on Feb. 24, that dream was abruptly shattered. Katelynn was about eight centimeters dilated when a doctor stepped into the delivery room and said, “I’m so sorry to tell you, but Lilah’s in the ER.”

Still in her hospital bed, Katelynn learned that Lilah had suffered a seizure at home and been rushed to the emergency room. A scan revealed a mass on her brain. While the tumor wasn’t causing pressure or swelling — meaning surgery could safely wait until the following week — the fear hit immediately.

That same day, Lilah was transferred to a children’s hospital for an MRI. Before leaving, she was allowed a brief visit with her parents. The MRI confirmed what they feared: the mass was a stage 4 tumor.

“At first, we tried to stay hopeful,” Katelynn tells PEOPLE exclusively. “We thought maybe she’d have surgery and everything would be fine.”

On March 3, Lilah underwent brain surgery. Doctors successfully removed the entire tumor. But later that week, the full diagnosis arrived over the phone: ATRT — atypical teratoid rhabdoid tumor — a very rare and aggressive tumor.

“When the pathology confirmed it was one of the most aggressive tumors, we just cried. We cried for three days straight,” Katelynn says.

Surrounded by both sides of their family, the couple leaned on their support system — but fear lingered. “In the quiet moments, just the two of us, I remember looking at my husband and saying, ‘I just don’t want her to die.’ ”

Soon after, doctors walked them through the treatment plan. For ATRT, there is essentially one protocol: two rounds of induction chemotherapy, three rounds of high-dose chemo with stem cell rescue, and six weeks of proton radiation. Their oncologist consulted nationwide specialists to confirm it was the best course.

“With Lilah’s cancer, if you don’t treat it, there’s a 100 percent chance she’s going to die,” Katelynn says. “Because it’s so rare, there aren’t many treatment options — there’s really only one protocol that’s been used for the past 25 years.”

Both Katelynn and Tyler stepped away from work to care for Lilah full-time while adjusting to life with a newborn.

Lilah first began treatment at Brenner Children’s Hospital in Winston-Salem before transferring to Duke Children’s Hospital in Durham for most of her chemotherapy. When it was time for proton radiation — which Duke does not offer — the family temporarily moved to Philadelphia so she could continue care at the Children’s Hospital of Philadelphia.

The early stages were the toughest. “She had a lot more side effects,” Katelynn says. “But where we’re at right now, honestly, we’re just so happy. People don’t understand how you can be happy during such a hard, dark time, but she’s alive right now. She’s here with us, acting very normal, and I’m going to make as many happy memories as I can with her.”

Through every stage, Lilah’s spirit has endured.

“She’s always been so happy — even as a baby, she had the best temperament,” Katelynn says. “Everyone called her a ‘trick baby’ because she made everything look easy…she still wants to go up to other kids and play or say hi to people,” her mom says. “She hasn’t lost that spark.”

As a way to process the whirlwind of emotions, Katelynn began documenting their journey online on TikTok and Instagram. At first, she took a three-week pause, unsure if she wanted to share their story publicly. But she soon realized posting was a way to cope and process everything she was feeling.

Then she noticed something unexpected: her posts were reaching other parents, who messaged her to say that her updates helped them feel less alone. That connection changed everything.

“That’s when I realized I wasn’t just sharing for myself anymore — I was doing it to raise awareness,” she says. “Pediatric cancer is so real. It’s not as rare as people think. And brain tumors just surpassed leukemia as the number one cause of cancer-related death in children.”

“Everyone is just one diagnosis away from their life changing forever,” she adds. “For us, it literally happened in one day — one day she was fine, and the next she wasn’t.”

Then came an unexpected bright spot. Lilah discovered Swift’s new album, Life of a Showgirl. One day, when Katelynn was playing the record, Lilah perked up: “Mom, that’s Taylor Swift.” Katelynn pulled up the “Fortnight” music video — and Lilah danced.

Of course, Katelynn recorded the moment. Mid-dance, Lilah, now 2, looked at the screen and declared, “That’s my friend.”

“I didn’t even realize what she said at first,” Katelynn says with a laugh. “I asked, ‘That’s your friend?’ and she said, ‘Yeah.’ And honestly, it feels like they really are.”

When she shared the adorable clip on TikTok, it quickly went viral — and commenters tagged Swift.

“I joked to my husband, ‘People really think Taylor’s going to see this,’ ” she says. “He told me, ‘You never know.’ But I had no real hopes she actually would.”

A few days later, she found out she had.

Tyler called from the airport with the news about their GoFundMe: “Taylor Swift just donated us $100,000.”

“At first, I thought he was joking,” she says. “For about 30 minutes, we questioned if it was real. But then we saw it come through on the back end of GoFundMe, along with a message that said, ‘Sending you the biggest hug to my friend Lilah.’ That’s when I knew Taylor really saw the video — and she meant it.”

The moment still feels unreal. “Knowing that she saw our video makes me so happy,” Katelynn says. “The donation is incredible — it helps us so much — but the fact that she took the time to watch, to care, to send that message… it means everything.”

Lilah doesn’t understand fundraising — but she knows friendship. When they filmed a thank-you message, she saw Taylor on the iPad and once again said, “That is my friend.”

“I told her, ‘Yes, baby — Taylor Swift is your friend,’ ” Katelynn says with a smile. “That’s just how she sees it. And honestly, I love that.”

Katelynn adds how support has only grown since Swift’s contribution. “Her donation started this, and the Swifties took it and ran,” the mom says. “They’ve almost doubled her donation now. I feel like I can’t say thank you enough.”

“I’m so grateful that more awareness is being spread about pediatric cancer and about ATRT,” she adds. “Even if someone didn’t donate — just seeing our story makes us feel seen.”

The family hasn’t heard directly from Swift outside of the donation — and they don’t expect to. “She’s a very busy woman, and what she did was more than enough,” Katelynn says. “I just hope she knows how grateful we are. It felt like she gave us the biggest hug.”

Now, as they plan for the future, Katelynn’s focus remains on the present — on Lilah’s joy, her comfort and the memories they can make together.

“To be completely realistic about my hopes and dreams for her, it’s just that she has a happy life — no matter how short or long it might be,” she says. “I want it to be filled with memories, experiences, and joy… I just want her life to be joyful.”

“We have so many plans. We want to start a nonprofit, but now we’re like, okay — once we get through this storm, I really, really do want to start something. We’re already brainstorming different ideas that aren’t already out there,” Katelynn adds.