This quest is not available in game.
Speak with Gornek. You recall Kaltunk marking your map with his location and mentioning that Gornek resided in the Den, a building to the west.
Finally, you are of age, <name>... of age to battle in the name of the Horde. To conquer for the glory of the Warchief.
<Kaltunk looks you over.>
You will do nicely.
No doubt you wish to find a great dragon or demon and strangle it with your bare hands, but perhaps it would be wise to start on something less... dangerous.
Report to Gornek, he should be able to assign a task better suited to a young <class>. You will find Gornek in the Den, to the west.