I also took the learning-as-you-go approach when I started out here, though it's a heck of a long time ago now. I would say that as long as you try and stick with a concept that is relatively simple and doesn't step right on something that would typically (regardless of setting) be controversial then you should be fine. You can always add elements to your characters background as you learn more, and put the fact that it hasn't been in play down to them either not talking about it or not remembering it well, to name a few things.Â
I wouldn't say that XIV is the most difficult of settings to navigate in without knowing absolutely everything, and you can always start by trying to figure out the lore that relates to your character the most - like, if they for example stay in Ul'dah, you could try to find out more about Ul'dahs society and culture. The lore section on this forum also has lots of interesting discussions and tidbits
I wouldn't say that XIV is the most difficult of settings to navigate in without knowing absolutely everything, and you can always start by trying to figure out the lore that relates to your character the most - like, if they for example stay in Ul'dah, you could try to find out more about Ul'dahs society and culture. The lore section on this forum also has lots of interesting discussions and tidbits