Why don't I know if I want kids?!!?How do I fix this?

Okay, I've been married for a year. We are both working with good jobs and are financially stable. I'm 27 and he is 30. We are both mature. We don't party or live extravagant lifestyles. We own our own home which is being renovated and have discussed kids and who will take time off ext. when/if we have kids. Why am I still not sure if I want kids or not? Why am I so terrified? Does this mean I should't have them? I want to start trying within the next year and I don't feel ready. Should I just try anyway?