“It changed my daughter’s life immensely,” Patty tells PEOPLE exclusively. “I hadn’t seen Ally smile and laugh like that in a very long time.”

Ally, who had been living with cancer since 2018, posted a TikTok video from that night that shows her standing in a bathroom placing the hat on her head, then putting her hand over her mouth. “what happened,” she captioned the video. She shared another video on TikTok from the moment Swift placed the hat on her head.

“no words to describe what it felt like to be pulled from my seats to the floor,” she writes. “I knew immediately. taylor was my first concert so many years ago. honestly such a full circle moment.”

Patty says she Ally were original Swift fans. When Ally was 8 years old, her very first concert was the Taylor Swift 1989 World Tour in 2015.

But in Sept. 2018, when she was 11, Ally’s life changed. She was diagnosed with Stage 4 Alveolar Rhabdomyosarcoma, a rare soft tissue cancer. Throughout her battle with cancer, Patty says Taylor’s music constantly “brought light to Ally’s life.”

Like so many fans, “she knew every single word to every single song,” says Patty, describing Ally as “kind, loving, fierce.”

Her love for Swift’s music was obvious. “Ally had her music playing when she was still able to shower, when she was organizing her room, when we drove anywhere. It truly is all she played.”

Ally even got a tattoo on her left forearm featuring lyrics from Swift’s song, “The 1”: “And if you never bleed, you’re never gonna grow.”

Through social media, Ally found connections with “Swiftie” friends who were also fighting childhood cancer. “It gave her an escape and a sense of belonging,” Patty explains.

It’s one reason that night in July was so special to her.

“We had the opportunity to meet Taylor’s mom Andrea at the concert,” Patty says. “We couldn’t thank her enough for choosing Ally for the hat, but I hope one day I can meet Taylor and Andrea to express how much that night meant to Ally.”

After five years of fighting cancer, Ally died on Nov. 13 at 16 years old.

Patty’s mom sees the significance. “As you know Taylor Swift’s favorite number is 13. Ally passed away on 11/13/23 at 13:40. The 13th day during the 13th hour.”

Since Ally’s death, her friends and family have taken to social media to share videos and words of love for Ally. Her friend Katie Histing writes on Facebook that Ally “loved Taylor Swift, cats, journalizing, music, cheerleading and so much more.”

“She was special,” Histing sontinued.

Another one of Ally’s friends Ava, who also loved Swift, posted a tribute to her friend on TikTok. “soulmates aren’t just lovers,” the video reads. In October, Ava had posted a compilation of photos of the two of them on TikTok.

“best friend appreciation post. (cuz I have the best one,)” she captioned the post.