I want to join the military
Are you serious? Why do you want to join the military?
I want to protect my country and kill terrorists
Supporting one's country and joining the military is a worthy goal. As it is your own future to decide, make sure it is what you really want and take some time to reflect on all your options.
I can't believe that everyone has told me how bad my idea is and how young I am to make such a decision. I don't need any of that shit.
Well it's your life and I think that signing up to defend your country is a very honorable way to spend it.