Also you don’t need the quest to start dragon flying. As long as one of your characters went through the quest already and got their first dragon mount… all of your characters can start flying right away in Dragon Isles. Check your mount tab.
Also your glyphs are account wide so any glyphs you’ve gotten… you don’t need to get that one anymore. So get all of them on one character and you won’t have to get the current glyphs ever again and you can talent into the dragon flying tree immediately.