I do not think being in the army is wrong. Every profession needs the presence of Christians so that the right things will be done. Christians are in the world but not of the world. In as much as we live in the world, we ought to work and if the bible is silent about the army being a wrong profession, who am I to say it is?
However, our conscience as Christians should also be a guide. If your conscience is not clear, then stay away from the army. once my mom got a job with the accounts department of the national lotteries in Ghana. She turn it down because she felt it is not right to work for the Lotteries. Let the Holy Spirit guide us into making right decisions. Pray about your professional choices and if you have doubts, then do not pursue it.