Ok, so how long does it take to level to 50? 3-4 days? How long would it take to get up to the 2.3 story? Well, if you do the main story as you level up, I'd say no more than a week to get access to ROG/NIN, and that's being ultra generous. If you really wanna be efficient, spend 2 seconds finding out what subclasses NIN needs to be unlocked and level them up to 15 (which takes a couple hours) along with your main class.