The course had been packed up for hours. Most spectators were long gone. Every single half marathoner had collected his or her race medal and headed to a celebratory brunch. All but one.

Kayleigh Williamson, 26, crossed the Austin Half Marathon Finish Line in 6:22:56, making her the first person with Down syndrome to complete the Texas race.

“I kept going,” Williamson told Runner’s World by phone. “[When] I hit the finish line I was proud of myself. My friend got me pretty nice flowers.”

Williamson and her mother, Sandy, have been running together for years. They began logging miles when the pair joined Weight Watchers to help them lose weight, starting with 5Ks.

“We were both over 200 pounds,” Sandy Williamson said. “Kayleigh had two autoimmune disorders, and one was life-threatening."

Eventually, Kayleigh needed surgery to have her spleen removed because of a severely low blood platelet count. "When the doctors discharged her immediately [post-surgery], that's when I knew I had Wonder Woman," Sandy said.

Once Kayleigh started eating better and running, her platelet count went up, leading to the remission of her Graves’ disease, which results in the overproduction of thyroid hormones. (She is still in remission today.)

Kayleigh  has always been active. She joined the Special Olympics Texas basketball team when she was 13, and she still plays regularly. But running made her a more confident and healthier person, her mother said.

In 2016, Kayleigh wanted to participate in the Austin Distance Challenge, a series of five races that culminated with either the Austin Half or full Marathon on February 19, 2017. She completed the Run Free Texas 8K and participated in the Run for the Water 10 Miler, but she struggled in each event because of leg and ankle pain.

“Running is not that easy,” she said, referring to her leg pain.

When Sandy decided to run the half marathon, she worried about where she would leave her daughter.

“I can’t just leave her at the finish line,” she said. “Leon [a running group teammate] offered me the half marathon and a spot for Kayleigh. I thought it was funny and figured Kayleigh would say, ‘Yeah, mom, no way.’ But she said she wanted to do it.”

After struggling through the 10-miler in November, Sandy took her daughter to RunLab Austin, a facility that specializes in running biomechanics, gait analysis, and running-specific rehabilitation. That’s where Kayleigh met Kimberly Davis, D.C., and CEO of RunLab Austin, whom she has been working with since late last fall.

“Not only did Kayleigh have ankle issues, people with Down syndrome have hyper mobility, meaning they’re super flexible in their joints. It’s really difficult to do basic movements, so we worked on her biomechanics,” Davis told Runner’s World.

“She’s made so much progress, and the fact that she was able to get through [the half marathon], considering the position she was in three or four months ago, it’s super impressive.”

Race day was hot and humid, and the course is hilly. Three miles in, Kayleigh was the last one on the course, being tailed by the support van, said Davis, who was one of the people who ran alongside her. The water stations were packed up by the time Kayleigh reached them, but her growing support team would run to the grocery store to bring back supplies.

“We grew from four to five people to like 20 people,” Davis said. “It was the coolest thing.”

There were many opportunities for Kayleigh to hop into a support van and hitch a ride to the finish, but she wouldn’t hear of it.

She demonstrated that same can-do attitude in the 8K in October.

“I tend to be overbearing at races, constantly saying you gotta go faster. They’ll sweep you if you don’t go any faster,” Sandy said. “But she always pushed back, rightfully so. She said, ‘No, this is my dream and I’ll do what I want to do.””

So when the two approached the Austin Half Marathon finish line surrounded by their entourage, Sandy said she was humbled.

“When she hit that finish line, I went from being a mother thinking she has to be protected from the world to thinking she’s a woman who can take on the world.”

Sandy hopes her daughter’s determination will inspire others with Down syndrome and special needs to take up running. “[Kayleigh] tells me to ‘toughen up, buttercup,’” she said.

Kayleigh is already signed up for the 2018 Austin Half Marathon, and her next race is the Capitol 10K in April. Her running playlist is already queued up.

“I like Britney Spears,” she said. “My favorite is Britney Spears ‘Baby One More Time.’”

This article originally appeared on Runner's World.