I began playing it on 4/11, had the WAR up to 18 and got my subjob on 5/22, I only got to play it a couple days a week also. If you devote enough time, you can get up there quick. I took time to do some quests and stuff like that too, and you will need the money. I also recommend you start selling at the auction house immediately, that's where you can make you money.
I chose a WAR as my job because, like I said, I want to be a DRG eventually. I chose the MNK as my subjob because it will get me a boost in HP as well as counter attacks and stuff like that. I plan on getting my MNK to lvl 15 then going back to my WAR, who will not only be able to wear decent armor, but also have some of those monk like skills and I will be one killer Tank.