KABUL, Afghanistan — The face of war shows the youthfulness of a new generation.Although many veterans have already served two or three deployments, others are experiencing their first overseas duty. I saw their youthful faces when visiting the USS John C. Stennis and Kandahar Air Field in 2011 and now I see it again at Forward Operating Base Shank and Camp Phoenix.When I was in my 20s, I was entering my profession and trying to establish myself. I had responsibilities, but not the responsibilities our young sailors and soldiers perform day after day. During my time here at Phoenix, I …