Yeah, I got about the same when I put myself in as "normal"... did she put you in as an athlete or "normal"? I would go back and try it as an athlete just for the hell of it... it will probably be more accurate...
I've also noticed, as Shadow said, it varies a lot. I've measured myself same time of day, same weight, same everything, and had it be 2% off from the previous time. It's not as accurate as it should be, but it's probably more accurate than a retard with calipers