So, the bike doesn't fit. Damn.

[bcipam]

They sold you a 15? I'm not an expert, but if that is in inches, that puts you at 38.1 cm. Pretty small. A 17 would be 43.18. (Am I doing this right people? 2.54 cm = 1 inch, but I know measurements are based on some esoteric stuff I haven't figured out yet!)

!

Not certain it works that way. I am 5'8" and my mountain bikes are 17 and 17.5 and the road bikes are 51 and 54. The road bikes are just different geometry. The 51 has a much longer top tube, the 54 is shorter, more WSD. It really has to do with the bike's design and where the manufacture measures height. On some bikes I can ride a 56! A person say 5'3 - 5'6 would ride a 15 mountain bike.

I can't imagine the OP on a bike bigger than 15. A 17 would be way too tall! The most important measurement is actually length not height. If the OP can comfortably reach the shifters and brakes, then the bike is probably the right size. I would even think at 5'3" she might try a 13...