Baby Fever at 20?

I'm 20 and my 21 year old husband is in the Army. Not only am I a wife, but I am a stepmother to his 1 year old daughter. We dated for a while back in high school, but we had our differences and disagreements. So we did what most young couples do and parted ways.Not long after, he got into another relationship. 3 years later with very little contact via phone, he comes back and wants to get back together. He was very honest with me and admitted to getting his girlfriend pregnant when we were separated. Their relationship of course didnt work and he wanted to get back with me. After dating for while, that connection we once had came back because I had never stopped loving him in the first place. He proposed to me before he left for basic training, and we got married a few months later. During the time we were dating though, ever since I found out that he was a father, I began to have a desire to give him another child in the future. It became an obsession because I started to look up all-things-baby on the internet, such as signs of pregnancy, to motherhood hardships, to fertility issues. I never told him about this because I didnt want to frighten him. Of course I dont want a baby now. I am a sophomore in college and my major is nursing. Plus I work a part time job and just bought my first car. So I have a lot of responsibilities and I am just too busy for a child. My husband also has baby fever too and talks about having kids constantly. It's a beautiful thought really, but I already know that we're not ready yet. Still some part of me desires to have a family with him now. Am I just crazy?