So, since I'm probably not getting this game until Xmas.
What is the class that you guys recommend that I should go after first?
For the first class, you'd definitely want to get any of the Combat ones (Paladin, Mercenary, Archer, Magician). Trust me, they're infinitely better than being stuck with any knife, in which the latter barely does damage.
If you want to be more specific, it depends on your playstyle. If you'd rather stay a bit away from the monsters, you'd want to choose either Archer or Magician. The former class tends to be a nice option for those who aren't too familiar with Action RPGs, as the latter one starts out much weaker than you'd like even though it could become quite powerful if you take care of it.
If you're the kind of person who likes getting in the middle of action, Paladin and Mercenary are for you. The former is the easiest combat class to learn, simply because you can defend yourself with a shield in case you couldn't properly dodge monster's attacks. The latter lets you deal such high damage output, but you'd actually have to recognize your foe's attack pattern in order to time your attacks accordingly. That class is super useful when you're playing with NPCs or friends, since you can land devastating attacks while others are busy distracting the target monster.
Once you picked your first combat class (or all of them), I highly recommend you acquire all of the gathering and crafting classes. Trust me, you will want to mine, cut some woods and even snag some fishes while you're exploring Reveria. The materials you'll get from these classes will help you a lot when you get to craft items. The items you'll produce will sell you for quite a lot of dosh (the in-game currency), especially when you abuse the Hi-SP potion bulk trick early on the Alchemist class. You'll also wind up with even better items if you're really good on the crafting classes!
And last but not least, complete the whole story. Doing so will unlock an area as you progress through chapters and will help you level up quite quickly early in the game. I've mentioned that on my very first post of the Fantasy Life General Thread for the "Getting started and completing the main story" section. There's no excuse to not complete the story immediately after you've gathered enough classes!