First, read the pages of the thread "DV-2011 AOS Only" for how you can adjust status smoothly.
Second, for any international students or foreigners with temporary/non-immigrant visas to join the U.S. military, they need to have lived in the U.S. for a minimum of two years (Link:
http://www.nytimes.com/2009/02/15/us/15immig.html?pagewanted=1&_r=1). Since you have been in the U.S for only 2 months, I doubt any military branch will recruit you straightaway...unless of course you quickly and successfully adjust status and become P.R. which I suspect you plan on doing.
Third, your career path is your choice to make. You will acquire many benefits from serving in the military, but as you mention there are also dangerous trade-offs to it as you may end up in a war zone. And I don't understand why you need to join the military in order to become a network engineer. Sure, the army will pay for your education but you may also qualify for several scholarships once you become P.R. Anyway, the choice is ultimately yours. Best of luck !!!