The way things begins, we can be basically have any origin story.
Heck we can even have one where we are from another world/reality/dimension.
They really leaves thing open for "anything is possible but we just don't talk about it" scenario
I will not be surprised if they manage to introduce a Origin Story Side-quest storyline that it may have multiple path based on our character dialogue choice for their origin.
Though that maybe fun since GW2 played on a Origin Storyline for their character though rather limited with end results it was nice little thing to touch for the player characters.
