Pregnancy

So my partner and I have been together 3+ years. We are in our 20’s. And I am ready to start a family. I feel like I am at the point in my life. Marriage is not my number 1, so a baby before marrying has never been a problem for me. When my partner and I talk about it, he sometimes says yes he can’t wait and sometimes tries to brush it off. I’ve asked if he is nervous and he admits he is. I guess I am looking for advice, how did your S/O react or how did you and your S/O prepare to plan for children? Was it unexpected?