Wii Fit age:36

I recently had my body fat and all of that other stuff measured/calculated.
My weight is in the healthy range, as is my BMI and body fat percentage. I happy pleased with this, but I still want to improve. I haven't dropped any weight, but my body fat percentage is slowly improving.

I was feeling pretty good about myself until I tried out a friends Wii Fit and it told me that my Wii fit age is 36! There is nothing wrong with being 36, but I am 24. Naturally I was alarmed, especially since everything else the Wii board measured was impressively accurate. Why 36?

My friend explained to me that it has to do with my "center of balance," which basically means that I have bad posture.

Any ideas for posture improvement? If you remember from an earlier post I have lower back issues from a car accident and I know that my posture can contribute to the lower back issue as well. Any ideas?