Sorry to have to say this, but the truth is that this severity of male-pattern baldness (male pattern baldness) at such a young age means that your hair loss is so aggressive that it most likely isn't worth trying to fight it.
It is rare for male pattern baldness to hit a person so severely at such a young age, but it does occasionally happen, and when it does, it is an absolute death sentence in terms of your hopes of being able to successfully treat the condition. It is a cruel and unfair thing for nature to do to a young teenager, but nature can indeed be very cruel sometimes.
In my opinion, you are too young to start finasteride. It would be a major risk taking a 5-AR inhibitor at your age. In any case, even finasteride would be of limited help in cases such as yours. The truth is that your genes are programmed to want to get rid of all your hair very, very, very forcefully and ultra-aggressively.
However, in a couple of years time perhaps you could think about giving Avodart a try. For cases as aggressive as yours, Avodart would be a better choice of treatment than finasteride (although it does have a greater chance of side effects). However, even Avodart probably wouldn't be able to maintain the hair you have left for more than about five or six years after beginning treatment, because of how aggressive your hair loss is. Ultimately, nature will win the fight.
My advice would be to perhaps just shave it all off. In my opinion, it's not worth trying to fight it. Just let it go. Whatever happens though, don't let this affect your confidence and don't let it get you down. Just try to let it go, and work on embracing the shaven look.