I'm starting a project of building a new commuter bike (it'll be my first build), and I'm already stuck at the first step--picking a frame.

I've settled on a great frame that will allow me to mount racks, fenders, disc brakes, and all sorts of goodies, and the company is releasing a new line of the frame soon, so the current ones are on close-out at an incredible price.

The problem is that, because the current line is just about to end, no one has my exact size in stock.

I'm about 5'9" with an inseam of 31 1/2", so I've been told I should go with about a 54 cm frame. The only close sizes anyone has in stock are 52 and 58 cm.

How much of a stickler should I be about frame size? Will going down the 2 cm really be an issue, or is this something that can easily be adjusted through saddle height, stem size/angle, etc? Is there any reason it would make more sense to go up a bit in frame size to 58?

As I mentioned, this will be my first build, and I'm afraid I'll be exactly this annoying about every step of the process. I'd appreciate hearing what you all think.