I can honestly say that working on Mother/baby as a new grad nurse was the BEST experience of my life!!! It was great!!
I knew NOTHING about having a baby or what to do with one, and have NONE of my own, so yeah, I was nervous. Don't worry!! I find over and over again in my career that THE BEST learning tool is to simply listen and watch the older experienced nurses. 90% of what I know and the techniques I use today are a direct result of modeling the techniques of my 'elders.'
Another great and unexpected learning tool were the new moms themselves, if it was like their 3rd baby or something (and they weren't a crackhead or total nutjob). THEY taught ME sometimes!! LOL!!
Don't be scared...you've just got the normal new grad jitters. The best advice I ever got was from a nurse who told me to find someone on the unit that I felt comfortable with and to make her my 'unofficial' mentor. This is especially helpful if your preceptor isn't very friendly or bright (hey, it happens...). The nurse I made my unofficial mentor was a warm, down-to-earth, 3 time mommy herself who was really great. She taught me a lot and was a comfort on those stressed out days.