how can i tell if im underweight

Hi! I am 16 years old. I am female and I am healthy but skinny. How can I realize if I am underweight or not? Thx

It is very hard to say if a person is over/underweight especially during puberty.
People have different body types, so there's no single number that's the right weight for everyone. Even among people who are the same height and age, some are more muscular or more developed than others. However, there is a way to see this. Some experts have developed a calculator called body mass index, or BMI. The BMI formula uses height and weight measurements to calculate a BMI number. This number is then plotted on a chart, which tells a person whether he or she is underweight, average weight, at risk of becoming overweight, or overweight. There are many of these charts online. You can find them and use them but you need to know your exact measurements. Once you have calculated your BMI, it would be good if you asked a doc, or even a school nurse to help you figure out what it means.