Critical Care RN to OB??

So, here is the story...

At the time I first interviewed for a position at the hospital, I was told it was for an OB position. When I showed up for the interview, I was told the position had been filled, but there were several openings on different units where I could work until an OB position opened. I chose a critical care unit and have now been working there for over a year. Now, my questions...

1. How hard will it be to make the transition into OB from critical care?

And assuming I get the opportunity to transfer to OB...

2. What do I tell people when they look at me like I'm crazy (or so I'm told) for wanting to do a "total 360" in nursing?

I'm glad I was able to gain experience in critical care. It really helped me work on assessment skills, and helped me learn to be comfortable with things when they go wrong. I'm just looking for some feedback... thanks in advance.