When we first met Jadyn Schill four months ago at the Hospital for Sick Children, she was exhausted but extremely optimistic as she was about to become the world's first child to try an experimental form of chemotherapy.

Since then, "a lot has happened," said Jadyn, 13, this week from her home in Mount Albert, about an hour northeast of Toronto.

Dressed head to toe in pink, she practically dances up the staircase to show us her bedroom, filled with stuffed animals, craft projects and swag embroidered with her nickname, "Super-Girl."

Jadyn Schill, 13, has had brain cancer since she was five. She updates CBC Toronto on her condition. 3:38

Her positivity is infectious, but somewhat surprising given what she recently learned from her doctors.

"We were taken to the room, the 'bad news room,'" Jadyn explained. "That's where they tell you the news you don't want to hear."

That bad news is that the experimental treatment isn't working as doctors had hoped.

"The tumour is still growing," Jadyn said.

For the teenager who has been dealing with a brain cancer called Ependymoma since the age of five, this setback is nothing new. By her count, this is round seven in her fight with the disease.

Jadyn and her mother, Christie, photographed at SickKids prior to a surgery in January 2013. (Christie Schill)

Her medical team at SickKids plans to stop the experimental treatment and begin a chemotherapy trial. Schill said she agreed without hesitation.

"Why not? It could save my life."

Super-Girl Status

In 2013, SickKids dubbed Jadyn the most radiated child in Canada after her 123rd dose. That's the maximum anyone is allowed for life.

And so she'll try something else. In fact, her optimism has made her a natural pick for the hospital's latest ad campaign, called #SickKidsVs.

In a recent commercial, Jadyn and her mother, Christie, shave their heads together.

"Shaving my head in a room where we have spent so much time in the last eight years was a moment I will never forget," her mom wrote on her Facebook page after the video was posted.

"Many times sitting in the hospital you can feel so helpless. Not this day though! All we feel is fierce!"

Celebrity BFFs

Jadyn also delights in her time at SickKids fundraisers, where she's made friends with several celebrities.

Actor Billy Baldwin, a longtime fundraiser for kids with cancer, visits with Jadyn Schill twice a year. (Craig Chivers/ CBC Toronto)

CBC Toronto tagged along recently when she had brunch with actor Billy Baldwin at The Ritz-Carlton.

The two met in 2008 and get together about twice a year.

Rules to live by

Back in her bedroom, Jadyn tells us what keeps her smiling.

"Surround yourself with what you love," she said, pointing to the posters, Maple Leaf jerseys, and even a custom "Super-Girl" cape that hangs on her wall.

"Keep the positive attitude and you're good."