Becoming ready

Before you read through this, I'm simply posting this on truly trying to open up how I've been feeling yet it's hard to tell the actual person who needs to know it... well let me begin. For years the topic of kids have been huge between my partner and I... like when I mean huge amounts of baby fever and having crazy dreams( I mean him also of having realistic dreams of having kids) it's all we ever wanted. We are getting married this May... and I told him i wanted to wait for marriage first to try and plan kids. We have been together almost 6 years by the way and own a house together. Everything is in the rite path for us... but as each day keeps creeping by I'm getting this intense scared feeling...am I really ready to have a baby? To start motherhood? Change my life forever...I'm afraid. Why now when it's almost here? Why 6 months ago I would be thrilled for an accident and now I'm almost not wanting it because I feel not ready... I know most of you will say...PLEASE TALK TO HIM. I really can't. I've promised for the past two years... marriage marriage marriage and then we will try. Now marriage is almost here, wait never mind we will wait longer. It will crush him, this is all he wants. Kids. Every day of his life he DREAMS to start a family. And don't get me wrong-I WANT KIDS ALSO. But, I'm feeling scared at this time. There is so much going on in my head, is this normal? Has anyone has a planned timing when to start trying? Is is more scary then having an accident? I don't know... I wish these feelings weren't coming over me; but I can't help it.