The photos show the horseshoe pattern, so I would pin it on androgenic alopecia. The best thing to do is to see a doctor for a diagnosis and treatment, but I'm extremely certain what you have is male pattern baldness. There have been some people on this forum who have had amazing success on finasteride and minoxidil, but I will admit that many of them were probably not as far along as you are now. I would definitely recommend shaving it down as much as possible. Hair serves as a frame for the face. When you lose a certain amount I feel that most people frame it better by not having the weird shapes and diffuseness through shaving it down heavily or off. I shave mine down to a 1/4 inch because it gives it the appearance of a lot more density than is there. It is to the point where there is a gap between really short and long, where the hair does not look right because it needs to be longer to cover the area.
