The 15-year-old, who has won many medals in international competitions this year, is unfazed by having so little time in which to prepare. "I'm going to do my best," says the mildly mentally handicapped teenager, who studies at Choi Jun School, in Tai Wai. "I'm proud to be able to compete as Hong Kong's youngest representative at the Paralympics."
"I'll be competing with my two teammates in the same event. I hope all of us will have success at the Games."
The London Olympics finished only last night, but already the city is preparing for the other sporting extravaganza - the Paralympics - which feature physically and mentally disabled athletes, starting on August 29.
Hong Kong is sending 28 athletes, including Kelvin, to compete in seven sports.
Kelvin was seven when his mother, Vicky, first brought him to participate in a summer swimming course. "At first, I had no idea what swimming involved," says Kelvin, who will move up to Form Three in the next school year. "But very quickly it became my favourite sport. I loved the speedy feeling in water."
His enjoyment led him to attend summer swimming courses in subsequent years.
By the time Kelvin was 11, he was attending regular swimming training.
This summer's Paralympics will be the first to feature events for mentally handicapped athletes since the scandal of the 2000 Sydney Paralympics.
In Sydney, the Spanish basketball team were stripped of their gold medals after perfectly healthy athletes were passed off as mentally challenged at the Games.
As a result, there were no events for mentally disabled athletes at the 2004 and 2008 Paralympics.
While many mentally disabled athletes have waited years for the chance to compete at the Paralympics, Kelvin is lucky in that he is taking part in the Games at such a young age.
Kelvin was selected to Hong Kong's B team of potential Paralympic athletes at the start of this year.
However, his speedy improvement since then led him to be invited to compete at April's British International Disability Swimming Championships, where he broke two Hong Kong national records and won two gold, two silver and one bronze medal.
His fine performances ensured he qualified for three Paralympic events - 100m breaststroke, 100m backstroke and 200m freestyle - and he was promoted to Hong Kong's Ateam of preferred athletes.
"I was so happy to compete in Britain with my HK team friends," he says.
"Besides swimming for medals, I also watched other swimmers compete and learned how to improve my technique."
After competing in Britain, Kelvin won three more gold medals at the Czech Open Swimming Championships in June.
The teenager, who turned 15 on June 2, was later confirmed as one of five mentally disabled swimmers - three boys and two girls - who will compete in London by the Hong Kong Paralympic Committee & Sports Association for the Physically Disabled.
Kelvin trains six days a week, with morning training held at Hin Tin Swimming Pool, in Sha Tin, and afternoon sessions at the Hong Kong Sports Institute. "I've focused only on training," he says. "I've been feeling quite tired, so to save energy, I'm just staying at home whenever I have any spare time."
Kelvin says he plans to make good use of what he has learned from previous overseas competitions and win a medal at the Games.
You can meet some of Hong Kong's Paralympic competitors at Plaza Hollywood, from 4pm to 6pm, on August 19.