Is it normal to think about it this much?

Lately, the past two months or so, I have been obsessed with babies and children. I have always liked children and loved babies, but wasn't too too interested. Now, people around me are having babies and my family friend has a 3 month old that I adore. I think about it and imagine having my own baby and toddler to take care of. I feel as though my maternal instincts are in overdrive. I have been trying to cook dinner for everyone, and take care of everybody. I have talked to my boyfriend of 4 years about it,and he seems to be on the fence, like he would be happy if we had a child, but he is not pushing for one or anything. I am about to be 20. I am just wondering if anybody else has been like this? I am almost sad and upset because I am not in a pregnancy right now. I am very, very mature, and have an income. I know that we would be thrilled to have a child and we would both be fabulous parents. What is your own experience with this?