My soldier

So there's this wonderful guy I talked to more than a year ago, he was 19 and I was 16.. I met him at a mall with my friend. He came up to me and asked for my number and didn't leave until I gave it to him. He was a soldier stationed in Kansas and he told me, he was only down in Cali "his home" for a couple of days until he had to go back. We talked and hangout every single day until he left. 3 months later he was finally home and done with the military. He came back home to me and we hangout again like a normal couple, it was just never titled. He re-enlisted and told me 1 month before he had to go to Germany for 4 years. We never left things with a promise or a breakup. We kept contact but nothing serious. When he was over there he told me to live my life and not to wait for him. I dated guys and everything, but I never had anything serious with anyone. Me and him started talking again just a couple of weeks ago. I'm 17 now and about to be 18, he's 20 turning 21 soon. I like him so much that if he would've asked for me to wait for him I would have. But he didn't want me to. Now that I am talking to him I feel all of those strong feelings I once felt for him. He's coming back in 3 more years. I'm not sure if he's staying here or re-enlisting Somewere  else. Would it be stupid of me to wait for him ? Or should I just keep contact with him and continue living my life like how I am now? ​