How Fat?

So last weekend I visited my parents, and among various other things they gave me were a set of bathroom scales. This is actually a set that has been knocking around for a while, originally bought my nan, who gave them to my mum because they were too complicated, and my mum never did anything with them. Anyway, I'm rambling.
So these scales. They are digital, and you tell them your height and it tells you your body fat (the 'complicated' part). Well it took me a while to figure out how to use them, but eventually I put my height in and get on. 210 pounds it says, which I knew. Its too much, although not as bad as it might seem at first glance, I am tall. Then it works out my body fat...
23.5% - I am nearly 1/4 fat. Now I'm not sure what its supposed to be, but I'm worried its meant to be zero, or close to that. If thats true then I am much fatter than I thought. I don't want to be 23% fat, something needs to be done...