I'm 5'4" and I ride a 52cm frame, but I have longer legs for my height - more like someone who is 5'6". Since you can't go try this bike out before buying it, the only thing I know of that you can do is to measure your inseam and figure out frame size from that. I used the equation inseam (in cm) x .65 = road bike frame size. I ended up with exactly the frame size that the guy at the bike shop recommended after having me try out a few different sizes.