Who else has this problem?? read...?

im 16 right, and i run like a cheetah, im active, i dance, im 5'2 and my measurements are 39, 32, 40 and i weigh 144 with a little belly but like whenever i take the BMI test thing online it says im at risk of being over weight....how can i possibly be at risk!? im more of the petite athletic type because like i stated before, i like to run and dance and im joining track this spring...so wtf is up with this scale? should i stop looking at it? who else has this problem..oh yeah also, what do guys really think about girls who are active but still have a little tummy?