It was a life-changing selfie.

Eight years ago, Megan Troutwine traveled to New York City to see her late cousin, Tony Martinez, who was living in Harlem.

“We had so much fun, just taking pictures and seeing the sites,” the good-spirited 33-year-old from Hudson, Florida, told The Post. “When you have family living there, your heart hits those streets differently.”

While in Midtown, the pair visited Rockefeller Center, and Troutwine stopped to take a selfie next to the nearby reflecting pool and fountains on Sixth Avenue.

“I looked at the picture, and my eyelid was drooping,” Troutwine recalled. “I thought it was odd, so when I returned home, I mentioned it to my neurologist.”

The doctor ordered an MRI, and on her way home from the scan, she got a call: They had found a benign mass inside her brain that was growing at an aggressive rate.

“I found out I had a meningioma,” which is the most common form of brain cancer, explained Troutwine. “This diagnosis, it is hard.”

Troutwine began treatment immediately at Tampa’s Moffitt Cancer Center. First, surgery was performed to remove the tumor. Then a follow-up procedure revealed the presence of another primary brain tumor — this one, a glioma.

Doctors informed Troutwine — now working as a health unit coordinator at Moffitt — that the tumor would continue to slowly grow, and that she’d likely require lifelong monitoring for her condition.

On top of that, doctors also discovered she carries the PTEN gene mutation, putting her at greater risk for developing other cancers.

Troutwine’s ordeal only recently came to light in a recent report on her local Fox station.

Since 2017, when she underwent a craniotomy, Troutwine was diagnosed with and treated for both breast and uterine cancer, she told The Post.

Throughout her tough treatments, Troutwine said she’s been fortunate enough to meet “some of the most genuine and inspiring people” she’s ever known.

“Cancer was not my first choice, but I wouldn’t trade where I am or what I have gone through for anything,” she said. She added that through her work now, she’s able to help “people in the most difficult time in their lives. So many people going through this don’t have that support system through it, so to be a vessel for that is a blessing.”

The church ministry student said she plans on pursuing a second degree — in public health.

“I have a heart for people and trying to help people in any way that I can,” Troutwine said.

Since her initial NYC visit, Troutwine lost her cousin to pancreatic cancer. She’s been back to the city only once — “to pay homage to the memories I shared with him.”