Definitely notify the recruiting centre of everything, legal, that you know. I imagine you have some idea as to why you're being charged, be it for whatever reason, just keep them up to date. They will likely wait until after you're proven guilty/not guilty before continuing on with your enrollment, but it shows them that you're honest, and your job can wait until you get this sorted out.
Just a quick idea. In my previous job, I've been charged with assault numerous times (I was a loss prevention officer). I was never convicted, because I never COMMITTED assault (I followed valid Use of Force protocols) and the recruiting centre understood that and agreed that the courts determined that I committed no crime.
So it all depends on what actually occurred. If you DID commit assault, and you get convicted, it may alter your chances to get into the military. But you should have known better. If you DID NOT commit assault and you don't get convicted, you should still get enrolled, it just may take a slightly longer period of time.
Either way, good luck!