What is the average weight for a 15-year-old at 160 cm tall?

That's not a simple question. Even the "charts" can vary greatly and much depends on your build. If you've muscular you will weigh more. If you're still growing and "stringy" you will weigh less. The most accurate method of determining if you are of the correct weight is to determine your Body Mass Index. The BMI shows how much of your body is lean mass and how much is fat. Women need slightly higher fat content in their bodies to maintain good health. There really isn't a simple answer to this question.