Joined: Aug 2008
Posts: 13,141
Likes: 2,165
From: Ann Arbor, MI
Bikes: 15 Kinesis Racelight 4S, 76 Motebecane Gran Jubilée, 17 Dedacciai Gladiatore2, 12 Breezer Venturi, 09 Dahon Mariner, 12 Mercier Nano, 95 DeKerf Team SL, 19 Tern Rally, 21 Breezer Doppler Cafe+, 19 T-Lab X3, 91 Serotta CII, 23 3T Strada
Yes, it certainly could be fine to go 56cm, but it depends on your body dimensions and the dimensions of the frame.
You've not given us enough info to say much more beyond that.