In my opinion i would work on getting to level 99 and getting SoA gear. Maat fight is fairly easy as white mage seeing as you only have to survive for a set amount of time/HP, bring a few Yagudo Drink, food and some meds. Check out
http://wiki.ffxiclopedia.org/wiki/Sh...ars/White_Mage for more info, assume it will be twice as difficult as you think. He will be easier on Dark day.
As for pre-SoA i would suggest doing CoP (easy these days and ring is still good), Abyssea (whm legs still used in end game) and Dynamis (gil and +2 gear).
I would also like to entertain leveling Sch, as a job it is just as useful as Whm endgame but it is also a capable Blm. Sch is a job that people are looking for end game these days for their stun spam. If not a level 99 job you will want it for a subjob.
Dark knight = MP sink, expect to be casting Cure, alot.