Overweight or underweight?

Hello,

So you're a female that is 13 years old and you are 5'2" and you weigh 99 and 1/2 pounds and you are very active.  It sounds to me like a good weight in my experience.  You could gain a little weight and come up to 105 if you like but honestly I think you should stay where you are.  You will naturally gain weight as you go through your teens as your figure will become more womanly.  That will happen naturally so I don't think you need to give it any help.  Most girls are worried about being to heavy, you are one of the lucky ones.  Sounds like you must have a good diet and if so keep up the good work.