Okay well I ride a 50cm and I am 5'3". Height is not the judge. It's leg length, torso length, arm length and other factors.
All of this "Well I have a friend who..." reminds me of "He's just not that into you."
I suggest going to a shop with a fit kit.
Or... okay I'll be the one... check out Craigslist, find some bikes with decent components between 50 and 53 cm, take a few test rides, if one feels good spend a few hundred bucks on it for a starter bike and see if you actually like road riding. Then save your pennies for a higher end bike down the road.
My bike is a flatbar roadbike from Specialized with Sora components. It has the EZ Fire shifters. They work great. I had them adjusted once when I first got the bike and had a little difficulty with shifting in one gear. I have since just passed 1000 miles on my odometer (yeah!!!!) and have never had a problem shifting.
I think WSD bikes must have a larger measurement than men's because mine is 51cm and I am 5'3" and it fit perfectly as soon as I got on it. Perhaps you would fit on a 54cm in a women's and something else in a men's style.