Because She Can: Cyclist and Mom Kristin Armstrong Wins History-Making Third Gold Medal at 42

In 2012, cyclist and two-time Olympic gold medalist Kristin Armstrong retired from the sport on top, for a second time. Just four years later, she's won gold again – only one day before her 43rd birthday.

Armstrong, who came out of retirement in 2015, earned her third gold medal in the individual road time trial on Wednesday, becoming the first person ever to win the same Olympic cycling event three times in a row, according to The New York Times. She's also the third oldest woman in Olympic history to win an individual event.

After celebrating her victory with 5-year-old son Lucas, Armstrong told reporters, "People have asked me, over and over: 'Why?' 'Why am I back?' And it's because I can."

"And I showed it today and I'm so proud and I'm so excited that I won my third gold medal," she said.

She added to NPR, "I think that for so long we've been told that we should be finished at a certain age. And I think that there's a lot of athletes out there that are actually showing that that's not true."

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Armstrong became a full-time cyclist in 2011, said the Times, after leaving behind a triathlon career due to osteoarthritis in her hips.

Now, Armstrong has a full-time job at St. Luke's Hospital in Boise, Idaho, where she's the director of community health. She's also Lucas' mom.

"For all the moms out there, I hope that this was a very inspiring day," Armstrong told NPR, noting, "Working at a great hospital in Boise, Idaho, and being a mom has been my secret weapon. It provides me balance and it keeps me on track and it keeps me super-focused."

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Lucas also learned a life lesson watching his mom, Armstrong shared with The Wall Street Journal.

"Today, the first question he asked me was, 'Mama, why are you crying? Didn't you win?" she shared, adding, "Now I have to teach him sometimes we cry when we win."

Armstrong doesn't plan to return in 2020 for the Tokyo Olympics, but is happy to end on a high note.

"I've never had so much fun in a road race in my career," She told the Journal. "I put it all out there."