You'll be just fine, so long as you're willing to learn from mistakes, the game really isn't as hard as the OP makes out. Yes there are a few nasty mechanics here and there but they're still doable with practice. If you're really as concerned as you appear about being dead weight then I advise doing your first run of each duty with a physical ranged job you really can't go wrong there. As for the community being unfriendly? Game fora always attract the worst elements of the community, peeps in game are equally as they appear (even if contractually obliged by ToS), if you ask for help I'd suggest at least 80% will happily walk you through stuff.