“You’re looking go-o-od. You’re looking go-o-od. You’re looking go-o-od.” The zumba leader sings her encouragement.

Looking at my reflection in the floor-to-ceiling mirror behind her, I think, You lie. I look like a bag of disconnected limbs–arms and legs flailing in different directions, none of which is following her lead.

There are times, I think, when I should just stay home and act my age. What am I trying to prove? I slip through a tight knot of coordinated bodies to hug the side of the gym and sip Gatorade. I’m sure I am sweating my electrolytes into an imbalance.

I’m new at this gym, and don’t dare look any of the other women in the eye. I’m too stubborn to admit I can’t do it. I’m in the middle of the room. Everyone in front of me can see my flailings in the mirror, and they’re probably throwing off the people behind me. Why didn’t I think to stand in a corner?

I end up sitting out during two songs.

After class, I grab my towel and Gatorade and head for the door. I do not look right or left. I walk directly to the locker room with my tail still tucked under and my tummy pulled in.

As I turn the corner into the locker room, I notice a wrinkled woman looking as sun baked as a mud pie. Great, a woman like me who probably spends her days on a lawn chair and comes here for the gentle yoga class I passed up.

“Looks like you love the sun,” I say, eager to tell my story to someone who understands that plunging into a zumba  class is not the best choice for a Medicare recipient.

“Only on weekends,” she says as she smiles. “I work 40 hours a week.” I gulp.  What kind of work does she do? Demonstrate how to knit in a yarn shop? “Pretty good for an 80-year-old,huh?”

I want to shrivel myself up into a ball and disappear. Instead I recover and say, “You must have great genes. What kind of work do you do?”

“I’m a cook. Work the early morning shift. Get off at one and come here to work out an hour. Then I help out a young friend in her day care. She’s got 12 kids, so is happy to see me come for a few hours.”

My mind revs up: this woman does not need zumba. Her 12-hour day makes my 45 minute-minus-two-songs zumba class seem like I’m the one who is knitting.

My 40-hour work week consists of reading and writing. I cannot fathom a 12-hour day standing on my feet. My feet have traveled miles of hospital floors, thank you very much, and they’ve told me they’re done.

I have to ask, “Do you plan to keep up this schedule until you’re 90?

“Sure am.” Her eyes shine. “Sure beats sitting around,” she says as she trots off.

I begin to wonder what I’ll be doing when I’m 80. Another ten years. I get an idea: tell my feet they’ve been slacking long enough. After all, I’ve been retired over ten years.

The Chicago marathon is coming up. If I take three zumba classes a week, I can be strong enough by Christmas to start training for 2012.

How about you? Want to join me?