1) People start RP at any and every level. Some people began playing the game only for the RP, and only leveled up to access other zones/maps/get pretty gear. I came from the opposite camp where I played FFXIV for the PvE at first, and got into RP after I had hit endgame. Playing through the game may give you some more ideas about the setting, but you can also find a lot of info on stuff here and from other people too!
2) That's a "it depends" thing. I'd recommend having a basic backstory that could incorporate some other people in your character's past, but you don't need to have something so fleshed out that your character has no room to grow either. Do what feels natural! The making connections board is a good place to get an idea of how to incorporate others in, or perhaps someone is looking for a character that could be yours!
Welcome to the RPC by the way!
2) That's a "it depends" thing. I'd recommend having a basic backstory that could incorporate some other people in your character's past, but you don't need to have something so fleshed out that your character has no room to grow either. Do what feels natural! The making connections board is a good place to get an idea of how to incorporate others in, or perhaps someone is looking for a character that could be yours!
Welcome to the RPC by the way!