What is the ideal weight for a 5' 6 17-year-old female?

The Average American girl your age and height is 129.5 - 131.4 lbs.

A healthy weight range is 106.6 - 152.4 lbs.

That range is just an indication only based on height. Factors such as race, athleticism, etc. can effect that. If you are concerned at all about your weight, go see your doctor.