As a new player who started out as a marauder, here is my basic experience:

It does start out pretty simple and The Smith lessons are super helpful. It took me some time to get to 50 since this was before the MSQ exp boost, so I was given more time to learn. The rudest comment I got was 'why on earth wouldn't you use tank stance' in one mid-level dungeon, which is not rude at all (of course I'm sure they complained about it in private later). That was when I learned about stances!

That said, you need to have fast reactions if you start out as tank or healer, not to mention a thick skin because there are some buttheads out there and tanks/healers are easy targets. Otherwise, the safest type is gonna be one of the long range DPS classes (archer or thaumaturge or arcanist) just because it lets you stand away from the action somewhat. Fights get more demanding later on no matter what the class, so be ready to learn and experiment and ask others for advice!

(PS I still do stupid things as a tank like chase butterflies during Ravana but at least I don't fall off the cliff on Titan normal now. Progress!)