After-school Taekwondo practice at Coppell Taekwondo Academy is where strength, discipline and resilience are taught.
"What do you like about Taekwondo?" NBC 5's Kristin Dickerson asked 13-year-old Hannah Derr.
"It's a really good workout, and it's made me feel a lot more confident," Hannah said.
"These are most of my belts, not including the senior belts," Hannah said, while pointing to the row of colorful belts neatly presented on her bedroom wall.
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Taekwondo is Hannah's first sport to play.
"When I first started, it was very hard for me," Hannah said. "It was hard to do — to memorize forms, it was hard to spar. I just wasn't sure I could do it."
Hannah's mom, Ellie Derr, said Hannah was born with a rare visual disorder. She was slow to start crawling and walking, and then at 7 years old, Hannah was diagnosed with Asperger's syndrome.
"And so, of course, my husband and I were very worried, you know, 'What does this mean for the future?'" Ellie Derr asked. "What kind of limitations is she going to have?"
"And here she is, 13, and she seems to have no limitations at all," she said with a smile.
"I have no doubt that she will continue to far exceed our expectations of her," said Hannah's dad, Dave Derr.
"Jumping jacks, go! One, two," a teacher shouted at Taekwondo practice, as the kids continued their workout.
Along with the physical demands, Hannah said her condition makes it hard to focus — so following the structure of Taekwondo can be even more difficult.
But she pushed through, and after four years of training, "This is my first senior black belt certificate," Hannah said, while holding the award that was pinned on her wall.
She's also earned a collection of medals.
"These are really heavy," Hannah said, while holding all of them together.
"She's just accomplishing everything she sets out to do, and she's just pretty amazing," Ellie Derr said.
"Hannah's incredibly resilient," Dave Derr said.
She likely gets that resilience from her mom.
Ellie is also in a battle of her own — against a rare form of cancer. She said Hannah is her inspiration to keep fighting it.
"There's been times when it's been so hard I haven't wanted to keep going, but she's definitely been my strongest motivator to stay here as long as I can," Ellie Derr said.
For Dave, watching the women in his life face their respective battles, "It really humbles me to see what they're going through and how they're doing it — with grace," he said.
Loving parents, who after worrying about Hannah's future early on, are now confident that she too can fight any challenge that comes her way.
Hannah also excels in school. She's in honors classes and started earning college scholarships in the first grade because of her impressive test scores.