The following is provided by WikiHOW:
"Yes, it's true: If you are old enough to do mathematics and you like chocolate, you might be able to figure out your age. By crunching these numbers (including the weekly frequency of your preference for chocolate), your age is mathematically revealed. It's a nifty trick for kids learning basic mathematics, who can practice it on adults and elicit reactions of surprise and amusement."
Try it out to see for yourself at www.wikihow.com/Calculate-Your-Age-by-Chocolate.