Dear slowtwitch fitter or folks who know a thing or two about bike sizing,

I'm being offered a 2013 argon e-112 at a great deal. However, the bike is size small and may be a bit to small for me. I'm 5'112, relatively flexible and lightweight. The guy sellling the bike is 5'7"-5'8" and comes with a 110mm stem but I could purchase a longer one if needed. Currently I'm riding a medium size canyon aeroad cf slx.

So could I be properly fitted on this bike or am I wasting my time?

Thanks in advanced.