You're up to level 16 already? You don't waste any time at all.
There's heaps of detailed guides in the guides & tutorials section of the forums
here.
Basically you don't really need to aim for one job this early. People do all jobs, but some like to do one job more than the others so they stick with that. Play around with all of them and see which one you like best. If you want to get started at level 20, trader is probably the only job available for a while because you will get your arse kicked if you try to go hunter or thief. That doesn't mean you won't get your arse kicked as a trader, you just have a slightly better chance of surviving.
