At your age you probably shouldnt start Finasteride, and certainly no Doctor would prescribe it for you. It would however probably stop it dead in its tracks right how. Maybe just try and ride it out until your around 20, assess whether its gotten worse (good idea to compare pictures) and then decide whether to get on meds or not. If you dont want to wait then you could start rogaine right now, be mindful however that when you start it, its for life (well until we find a cure anyway), you must be consistent with morning and evening applications to get results.