With Age Comes Wisdom Trophy in Chronos Before the Ashes

Each time you level up, you'll gain 2 Attribute points that you can put into 4 different categories: Strength, Agility, Arcane and Vitality. Arcane should be the last attribute you level up, to the point where I highly recommend doing it post-game, especially if you're going for Old Enough . Each "level" will cost 3 Attribute Points at the start of the game so you'll need to level up twice before you can increase this stat, making it quite costly. When you reach the age of 30, however, the cost will go down to 2. 
 
If you've already completed the game, just hit "continue" from the main menu and it'll pop you back into the game starting right before you fight the Dreamer. Since all your other stats are still at their 30+ ranks, you'll easily be able to just grind out killing enemies, dying to age up and respawn them, then rinse and repeat. Once you've put 30 points into Arcane, the trophy will unlock.