My first road bike was a 58cm Specialized Secteur. The LBS said that in would be ideal for an 1812mm rider, ( a tad under six foot) and I didnt know any better. I rode it for a couple of years but it never felt quite right. Just too big, despite a number of different stems. I bought a 54cm Cinelli Experience two years ago. I might have shrunk a few millimetres in height, but the smaller bike feels just fantastic. The lesson for me was that I need to ride the bike rather than rely on some dodgy sizing chart based on height. There are so many more variables than just how tall you stand.
Ride it.