Weight vs. Body Fat Percentage

Ok, I just had a fitness evaluation done at my new gym.  I'm 5'3", 122lbs with a BMI of 21, and in the normal range but my body fat percentage is 24.2 on the lower end of the "fair" range.  I go to the gym regularly--striving for 5 days a week, I do some cardio each time and weights at least 2-3 times a week and have for the past 3 years.  I don't really feel like I need to lose weight but I'd like to get my percentage out of "fair" and into "good."  I try to eat healthfully without obsessing too much, and would like to keep it that way.  Any suggestions?  I've got to admit this is kind of bumming me out.