text: at 12 years old, you're probably feeling a little self-conscious about how your body is changing.  you are right that a bmi of 18.7 is underweight, but as long as you eat a healthy diet, you should be ok.  (you most certainly do not weigh too much)\n\nyour body will continue to change, so the proportions you have now will most likely not be the proportions you have next year.  \n\nbe proud of your height!  you may not like being the tallest girl in your class, but as you get older, you will love how clothes look on you.  hold your head high!