Still, it was a fun hour in which everyone dripped with sweat, and I shook my hips like never before. My glasses flew off my face as I swung my head to the beat.
My Italian classmate Samantha Caccia, an interior designer and mother of three, told me: "Look at the instructor. Don't look at yourself in the mirror. It's better that way."
She was right. I didn't look as coordinated and graceful as I thought when I glanced at myself in the mirror that extended along the full length of the room.
The students in my class are an international bunch from Belgium, Canada, France, Italy, the Philippines and the UK.
Karine Barbier, a French teacher at the French International School, says: "It's so much fun! It is exercising without really noticing."
Though she has only been doing Zumba for two months, she has noticed positive changes in her body and plans to continue.
Dance is not only a good way to burn calories but also improves balance and coordination by engaging muscles at varying speeds, unlike jogging, where the same muscles are used at a consistent pace.
Students pick up the choreography after a few Zumba classes, which produces a wonderful sense of accomplishment.
Zumba is both physically and mentally challenging, says Briton Sally Bunker, a former international kindergarten principal.
"You have to be focused on the teacher's steps and remember them, and then try to do the session without having to rely on the teacher all the time. Brain-to-body coordination is not an easy discipline," she says.
Bunker has previous dance training and heard about Zumba from a friend.
She wondered if she could keep up at age 64 but found she actually excels.
Bunker takes her daily exercise seriously, and swims and does Pilates, too.
Zumba classes were brought to South Lantau, where I attend, by Eva Guidi Ewins.
The Belgian grew up in a dance studio where her mother taught after dancing as a ballerina in the Opera of Wallonie in Belgium.
Ewins and Clifford have known each other for more than 15 years.
"A lot of people were asking me about dance classes for adults, especially moms who were looking for something to help them get back into shape. So we started offering Zumba," Ewins says.
Zumba has spread to gyms, community centers and dance schools around the world.
The Bund turns into beach as the temperature reaches high