Social Security # for US Army?

I want to join the US army but I don't have a social security #. My only desire right now is to serve this country. I was brought here at the age of 1yr old. I'm currently 19 living as a bum in my parents home. I have gone to the recruiting station but they always say the same thing. "are you in the process of obtaining one" i say no, but that is where I get stuck. what do I do? Please help. If I can't make it into the army, I'll simply go back to a country I never knew, its hell for me here, I can't even work. So I'm begging, please help me.