I am exactly like that.
I already know I wanna be a Scholar/Astrologian later on, so I am taking my time and levelling THM, CNJ and now ARC.
Also helps quite a bit to have access to Cure as a THM I must say, and Aero for ARC.

Now I am preparing my ARC (the class I want to progress with for now) to hit 15 and do my Hall of the Novice and first dungeon with.