I have been seeing more and more teenagers with similar concerns. I think part of it is because of increased awareness. At this stage, you have high likelihood of getting good response out of treatment. Having said that, every treatment should start with looking into the causes of hair loss. I will suggest complete blood work including hemoglobin and iron levels and thyroid hormone levels. From this photo, it looks like you have androgenic alopecia. Genetics also play a strong role especially when hair loss is seen this early in life. PRP therapies, optimizing nutritional status with vitamins, minoxidil, and laser caps will help restore the hair. I usually recommend a maintenance program once desired results are achieved.