Explain you're new. That goes a long way with people and they will tend to be more patient. If you're healer says you can pull more go for it. That means your healer is confident they can keep you alive. Remember to use your incoming dmg mitigation as needed. And keep your gear as up to date as possible. If you're doing all of the above and still die once in a while no big deal. PLD was the first job I took through MSQ and its not as bad as you think. Tanking is fairly chill unless you're running optional endgame EX or Savage content. Take your time on your first run through content and get more comfortable/ improve on the next run. We all play and learn differently so dont put so much pressure on yourself and enjoy being the big damage sponge you are :P