I'm not sure whether to Tank or DPS

[Akamukai]

Scratch that. New comment. xD

For tanks, your wait time will indeed be shorter, but honestly I'd just make friends with somebody who likes tanking sometimes also. People always talk like this game is a solo-game with the ability to queue, but there's a community out there. If you haven't found some in-game friends to do content with, you're missing out.

Regarding pressure on Tank vs. DPS, I don't really see a huge difference. On easy/standard content, nobody will be pressured because it's casual. On harder content, DPS can wipe the party as easily as the tank, because mechanics require everyone to do them. You'll naturally have some more attention as the tank since you aren't stacked, but if you're messing up as a DPS, we'll notice. Rather than trying to focus on a DPS vs. Tank, I'd play around with the specific classes themselves. My bard and Samurai felt quite different, as did DRK and PLD. A great way to play around with classes is to spam some Palace of the Dead. Good XP, and its a fast way to test out the classes.