Absolutely this. The thought of LFR is terrifying to me purely because of how much of a toxic cesspool it is, and I'm DPS. I'd love to tank or heal, but I'm far too frightened. I'll wait till I get a guild sometime next expansion. It's honestly a shame that the playerbase is so intent on tearing itself apart limb from limb and burning itself alive (in some aspects).
As for advice, OP, I know how you feel, but I don't have any since I barely raided this expansion and I'm too nooby to tank anything but leveling 5 mans. But best of luck to you! I hope all goes well in your endeavors, and do try to remember that it's not always your fault. Criticism can come whether it's valid or not; you just have to try take it in stride.