is 15 years old for female too young for surgery invasive to the bone? such as facial contouring - jaw reduction, chin reduction, brow bone shaving?
The surgeries you have mentioned in your question are very invasive surgeries. My personal opinion is to see a Board certified Plastic Surgeon with your parents (Since you are a minor). and discuss your diagnosis and options.
Since your question is under the "facial feminization" heading, are you transitioning ? if so My personal opinion is you are too young for that type of surgery even if your parents agree to the surgery.
The original requirements in my opinion still stands:
1: Have to be under a psychiatric care for a minimum of two years
2: have to live the opposite sex for two years
3: Hormonal therapy under the care of an endocrinologist for two years.
Then will discuss the surgeries you desire and what can be done.
Yes, the most appropriate thing is in principle to be of legal age and that the decision be made with sufficient maturity and awareness of the change you want to make. Until then I suggest that you keep yourself in continuous psychological evaluation until the moment of decision making arrives.