Well not to disagree with UPT-hopeful, but it can be done with 0 face time. The guard unit I was selected for I had never been to visit. I am sure visiting will not hurt you by any means, but it is not always a necessity. Make sure when you do interview/visit to be confident when talking to the people you meet. Be respectful, but remember, they were in your shoes at one point. Not that I am some old wise man, Just my .02 on the matter.
In answer to your?'s
82 P
72 N
99 PCSM
131.0 HRS
I am only 22 so age was not a factor for me