Picking a company happens shortly before the quests that unlock the job stones(sylphic management for most classes), so thats a likely culprit. The quest seems rather arbitrary, but they probly picked it thinking that few people would be almost 10 levels ahead of the story by that point in the game. Honestly the level 30 ability isnt amazing for BLM. Maybe work on the story and when you get to 35 go back and get the stone plus do the 2nd quest while youre there? Its a thought.