What is the ideal weight for a 16 year old girl with a height of about 152 cm?

Hard to say: An ideal weight must account for muscularity, bone structure and general health. Charts that give you a body mass index are great for general population studies but often fail the individual. At 16 the "desired" BMI is 20.5 which yields a weight of 105 lb, but the middle of normal is between 96-118, the full normal range is between 87-126.