I just got my first road bike, and thank goodness I found a great LBS. I had never test ridden a bike beyond the parking lot, so I checked out the area and looked for a good route. Then, before I took the first one out for a spin, I asked the sales guy where he would recommend I take it out. You want to try it out on more than just side streets and flat terrain. They were really helpful. If you are in a good shop, you should feel comfortable asking. They want to help get you on the right bike.

Try all kinds of bikes. I went in thinking I was going to be comfortably fine on a men's bike, and I happened to come home with a WSD. And I'm 5'8". It totally depends on the person and how they feel most comfortable.

Good luck, and have fun! It's exciting!

(Edited for spelling!)