Its Just a Number on the Scale...

Your only as young as you feel... If that's true then what should also be true is ... You are only as fit as you feel..

Numbers may not lie, but each number by itself does not speak the whole truth. Especially if you have a scale that reads a BMI. The BMI is notoriously inaccurate in making calculations for women in order to determine the healthy weight, see what I mean here or here.
Generally speaking women of different body types, may not have the most accurate results, women have all sorts of different frames, although I am 5'4 and healthy, my scale repeatedly tells me I need to gain 5+ lbs, despite the fact that my BMI is within a healthy weight AND my clothes are too snug, and my measurements are BEYOND the healthy proportions for my frame.