I am 26, my girlfriend is 24, we have been together for 6 months. I am concerned about being childfree and this has been a huge argument of ours.

I am a teacher, this is my first year. My student teacher, 24, and I started seeing each other. When I was younger, I used to think about how great it would be to be a father. But more recently, I have been absolutely terrified about being a parent. I think I would hate it, but I don't know how much of this is based on fear of the unknown. <br><br>Anyway, my girlfriend and I have been having this HUGE argument. She wants kids but I don't know, and I am terrified that I change my mind after marriage, and really don't want to have kids. She thinks I should do whatever it takes to do what I know I want, and says that if I'm unsure it means I should have kids.<br><br>Thoughts, please.<br><br>EDIT: She grew up without a father. I think this changes things.