Six years ago, she was just another kid frolicking at water parks to escape the summer heat. However, at the recent Chinese National Swimming Championships, Yu Zidi stood atop China's swimming elite — and the world is struggling to believe she's only 12.

The swimming prodigy emerged as the brightest young star at the championships held from May 17 to 24 in Shenzhen, Guangdong province, after producing a string of eye-popping performances.

Yu Zidi, 12, has already secured three "A" cut qualifying spots for the World Aquatics Championships in Singapore in July. XINHUA

On May 24, sporting her signature swim cap adorned with a cartoon dog pattern, Yu clinched the women's 400m individual medley title by a staggering margin of almost two seconds. She dominated a competitive field, setting a personal best time of 4:35.53, impressively surpassing the world championships qualifying standard of 4:43.06.

Her time ranked as the fifth fastest time of the year, a feat that would have secured her fourth place at the Paris Olympics.

Just three days earlier, Yu claimed gold in the 200m butterfly event with an incredible time of 2:06.83, also the fifth fastest globally this year and another that would have garnered a fourth place in Paris.

That prompted the global governing body, World Aquatics, to post: "12-year-old sensation alert!" on social media.

"My lungs were about to explode! I didn't know my time; I just focused on my pace, stroke by stroke," Yu recounted.

She started the week-long China championships by taking second in the 200m individual medley behind Paris Olympian Yu Yiting, with another worlds-qualifying time of 2:10.63.

Yu Zidi performances secured her three "A" cut qualifying spots for the upcoming World Aquatics Championships in Singapore this July.

"I'm really excited and hope to achieve good results, but since I have never been to the World Aquatics Championships before, I'll just focus on doing my best," she said.

Yu Zidi started swimming at six years old during a summer vacation.

"That summer was too hot, so I went to the water park with my dad for fun. Later, because it was a long vacation, I often went to a swimming pool to cool off, and a coach noticed me there. At the time, I thought, why not give it a try? So I tried, and here I am now," Yu Zidi recalled.

After that, she began training as part of a swimming team every day after school.

"It was crazy busy — barely any time to play, but fulfilling," said Yu Zidi.

Li Chao is the coach who first spotted Yu Zidi in 2019.

"She has a great feel for the water and isn't afraid, even when diving," Li recalled. "At first, Yu (Zidi) trained alongside kids five or six years older than her. What stood out the most was her incredibly strong legs."

Yu Zidi's idol is China's middle-distance freestyle swimmer Li Bingjie. In one of her school essays, she expressed her aspirations: "I hope to become an Olympic champion like her when I grow up — I want to experience that feeling for myself. Even though it's tiring, as long as I can keep swimming, I'll continue striving to bring glory to our country."

Yu Zidi shared how Li Bingjie personally coached her on poolside techniques — from refining turns, to underwater kicks — and patiently explained training plans that she initially found challenging to grasp.

Despite being just 12 years old, Yu Zidi has already developed her own life philosophy through her daily training: "The most challenging moments often arise when you are on the brink of achieving your goal — that's when perseverance is crucial. I firmly believe that giving my all in every training session will ultimately lead to good results."