Should I get pregnant?

My husband and I have been married for a little over 4 months. I have 2 daughters ages 11 and 6 from a previous relationship. He doesn't have any children but treats my girls as if they are his own, they call him dad. He really wants us to try to get pregnant before he deploys next year. I know he really wants a child of his own, but I'm kind of on the fence about having one. I'm 31 and he is 28 and I thought I was done having kids before I met him. What should I do? Sometimes I want one, but most of the time I don't. I am so confused right now.