I feel your pain. Its funny to read everyone else's post and consider where they are and how they each have their own lives and arrivals at those places in their lives.
I have alluded to this in many of my previous post, but here goes...
I am in the Army. I have served for just over eight years and I cannot even begin to tell you the number of times that I have found myself in similar curcumstances. Its a common issue with service members across the board. Some join knowing that its a career, others join for the initial term, and still others (like myself) enlisted for the fun of it and became addicted to the life style.
So far everyone else is right. You are obviously feeling a lot of anxiety regarding the pending return home and the feeling that a desicion MUST be made soon. For you, there really is no race to make up your mind. For him, sure, he has to plan years in advance. Personally, I make a new 5 year plan about once every 3 to 4 years. After a couple tries it becomes easier. The first one cost me a marraige. She married me knowing that I was in the service, but wasn't quite ready to move as much as needed. The second one allowed me to finish 4 degrees, travel, and accomplish more than I had ever planned. Its all about timing, planning and staying flexible. "plan for the worst, hope for the best."
I know this will sound difficult, but all he really needs is the reassurance that no matter what he decides, you will be happy and stand by him. Its amazing how few women understand that men fight, work, play, for more than self satisfaction. We do it for you... the women in our lives. Well, you and our children, but that comes later. ;o) From what you have written so far, it sounds as though he loves you, and you him. You are both young and have will have many chances to do many things over the next 50 years. His Army, and your school, are just a couple of the things you will do.
Stick together, listen to your hearts, your minds, and relax. I don't know what his MOS is but from your post he sounds to be combat or combat support. If he likes the Army, then he should really consider reclassing in conjunction with this re-enlistment. If he choses right, he could be in school for the next year to two years and doors will open up for him like you would not believe.
So, No you are not wrong to feel the way you do any more than he is to feel the way he does. Its all just part of growing up and finding yourself.
When he comes home, let him bring it up. If he presses you to make up your mind with what you want. Start with the most important.. to be with him, happy, and loved. The rest will fall into place. If that isn't good enough, tell him the rest, but make it clear that he understand just how flexible your choices are when it comes to location and position. Unless he's a dork, he'll catch on sooner or later.
I wish you the best in all that you two do... know that you aren't alone and that there are many who although can't tell you how it is to be in your shoes, they sure can tell you what it was like to be in theirs....