(CNN)-- Dara Torres' quest at the age of 45 to make her sixth U.S. Olympic team came down to a single, furious lap.
She came up short Monday, finishing fourth in the finals of the 50-meter women's freestyle at the Olympic trials in Omaha, Nebraska, behind a trio of women nearly 20 years her junior.
Torres took to the starting block both a serious contender and sentimental favorite. She's a 12-time medalist who at the 2008 Games earned the title of oldest American swimmer to win an Olympic medal.
By the time she touched the wall, 24.82 seconds later, Torres capped a storied Olympic career that began in 1984 at the Los Angeles Games with a gold medal in the 4x100-meter relay, her only event.
"This is it," she told reporters after she got out of the pool, indicating her long, career was finally over.
The top two finishers Monday secured spots on the U.S. team.
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Jessica Hardy, 25, won the race in 24.50 seconds, while 26-year-old Kara Lynn Joyce finished second with a time of 24.73. Christine Magnuson, 26, finished third with 24.78.
In the pool, Torres appeared to pass the torch, as she hugged Hardy and Joyce, congratulating them on their one-two finish.
Later, asked what she would most remember about a career with so many milestones, Torres said: "Probably the fact that I've hung in there this long."
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Torres took her time getting out of the pool, looking up at the stands where for nearly three decades she has been cheered on her in Olympic bids.
She then picked up her 6-year-old daughter, Tessa, who buried her head in her mother's shoulder.
"I think she's taking it harder than I am. I told her I would take her to London," Torres said.
Last month, Torres told CNN's Piers Morgan that the road to the London Games for her would be a tough one.
Her age was catching up with her, in some ways.
Torres, whose sculpted body has inspired awe in middle-aged women, was battling aches and pains that come with age. She talked about hormone changes that every aging woman faces.
She had undergone a state-of-the-art knee surgery after it deteriorated following the 2008 Games and spent two years recovering.
Much was made about her knee and whether it would hinder the fast start needed off the blocks to be a contender in the race. Her finish in the semifinals of the 50-meter freestyle earned her a third place berth in the final.
More than once, Torres walked away from swimming. She retired briefly after the 1988 Seoul Games but returned for the 1992 Barcelona Games.
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She then took a seven-year break before returning for the 2000 Sydney Games, where she would win two gold relay medals and first individual Olympic medals: three bronzes medals in the 50-meter freestyle, 100-meter freestyle and the 100-meter butterfly.
Torres took another break from swimming, missing the 2004 Olympics to focus on starting a family. She gave birth to her daughter in 2005.
She made her last comeback at the Beijing Games in 2008, where she earned a silver medal in the 50-meter freestyle and the title of the oldest American woman to swim for the U.S. team.
Torres' coach, Michael Lohberg, died last year from complication of aplastic anemia, a rare blood disease.
After his death, she decided to go it alone without a coach, though she did hire a trainer.
"I really wanted to finish the story that I started with him," she told reporters during a news conference following the race, according to transcripts.
But, she said, she knows he would have been proud of her performance.