A little scared of the future

[Vahlnir]

It takes me maybe a week to level a class to 70, but I need 1 - 3 months until I can play it on a decent level.

You level so fast and because the gameplay is not complete for many classes before you reach 70, and the whole mass pull and aoe it down is more or less a new thing at level cap wich was not that present during the level process, you will not be able to learn how to play before hitting level cap.

I would in all honesty just smack a training dummy around for a bit at lvl 70, so that even your AoE rotations become muscle memory. That alone helps. But looking up a guide outside of the game goes a long way too. Once you know the inner workings of your class things become much easier. As far as dealing with mechanics? Yeah, not really any other way to learn than to be baptized by fire. That comes back to knowing your class as well, so you know what you can do, when you can do it and how often.