Army boy

My boyfriend and I have been dating for a year and a half and he's going to the army in 6 months for 4 years and I'm so incredibly proud of him!!! I'm 18 he's 19 and I'm just a little scared of where that leaves our relationship... We both want to make it work except we haven't been apart for more than a week. I am EXTREMELY faithful as he is my first and he is also.. Help me ladies, I'm not sure what to do :(