Basically, the glitch you are hearing about is a error in the game which causes players who save their game in the outside areas of Lumiose City to be stuck, with all their buttons unresponsive (however, saving indoors is completely fine).
However, hopefully when you get your copy of X or Y, the patch for the glitch will come pre-installed and you should not have any problem. However, before you save in Lumiose City, it is probably best to check is it hasn't been installed previously. To do this, you must:
- Go to the Nintendo eShop. This is an application pre-installed on your 3/2DS that you can find on your home menu that you see when you turn the power on.
- The eShop should alert you that you game has an update once it is finished loading. If it does this, follow the steps it provides to update the game. If it does not give you a notification, assume that the update came pre-installed.