What is a fast and safe way for a 17-year-old female to lose weight?

No. If no underlying med problem, healthy weight loss requires eating the right whole foods, avoiding many processed foods, and staying physically active. Avoid any processed foods with sugar and flour, eliminate most foods with saturated and trans fats, and add plenty of vegetables and beans, many fruits and nuts, some whole grains, and wild salmon. Add regular physical activity and see pounds drop.
None. Fast is not safe. There is no fast way to lose weight that is also safe. The best way to lose weight is portion control and moderate exercise. It takes time and effort. Sorry, but despite all the hype there is no real way around this.