I'm 5'4 1/2. The bike I don't know. I only got on it momentarily. But, I am sure it is probably like 50cm. However, I decided to take the LBS route. I rather have the comfort of knowing that I can take my bike in and they can adjust etc...because of the life time guarantee. Not to mention I will have the manufactures warrranty.
I am not espcially handy w/ a tool...so I figure this might be the best route instead of paying someone everytime I need an adjustment made.