People have already answered better than I could, but I figured I'd add my 2 gil.
Really, as long as you aren't going out of your way to break or ignore lore, then go for it.
I might be a bit biased, though, as I've built the bulk of my character's pre-game history around an area that doesn't technically exist within the given locations we can visit in the game. Â I've tried crafting it in such a way that it feels like it could really exist somewhere on the overall map somewhere between the cracks of the locations we can actually visit within the game. Â It isn't in some far off land nobody has heard of, just a small farming village and the surrounding area that is far enough away from any major hubs that visiting them wouldn't be common (maybe a once or twice a year thing for supplies and possibly trade), yet not so distant that they wouldn't hear news now and then or have an occasional visitor passing through on their way to or from such places.
Really, as long as you aren't going out of your way to break or ignore lore, then go for it.
I might be a bit biased, though, as I've built the bulk of my character's pre-game history around an area that doesn't technically exist within the given locations we can visit in the game. Â I've tried crafting it in such a way that it feels like it could really exist somewhere on the overall map somewhere between the cracks of the locations we can actually visit within the game. Â It isn't in some far off land nobody has heard of, just a small farming village and the surrounding area that is far enough away from any major hubs that visiting them wouldn't be common (maybe a once or twice a year thing for supplies and possibly trade), yet not so distant that they wouldn't hear news now and then or have an occasional visitor passing through on their way to or from such places.