OP I suggest you look up phasing and how it works as a lot of this game's story content is phased.

Characters that a player has not encountered yet, such as Yugiri, are not visible to them. The game shows the world in a state that reflects their progress in the story. As others have mentioned above there are huge swathes of NPCs and other things that are invisible to a new player until they actually reach that point in the story. The same will apply to Yugiri with regards to the NIN job quests. Living Ninjas do not exist in Eorzea prior to Yugiri's arrival and her promise to train us. That means any NIN trainer would be phased out and invisible to a new player that has not completed the 2.2 story quests.