Pretty deep recession for a 17yo. There is really no way of telling how much hair you will end up losing, but starting at 17 usually isn't a good sign. Not that it will be much help, but have you seen your doctor. Although unlikely, maybe you aren't losing your hair due to male pattern baldness.
Finasteride really is the best weapon we have to fight male pattern baldness. I was just hesitant to recommend it to a 17yo. How are you responding to the medication?
bumbLooks like male pattern baldness to me, go see a good derm or hair transplant surgeon if you want a better answer.