So. As a tank, you should always remember that even though you're setting the pace of a run, you aren't actually obligated to constantly plow forward. Pace yourself by setting target markers before each pull, ensuring everyone is catching up, and assessing the terrain. This'll get easier with time.

To new tanks in new dungeons, please take this advice: Do NOT hesitate to tell your group that this is your first run, and that you will be taking it slow and steady. On very rare occasions you'll get a gripe or two, but even that is preferable to charging in blindly and slipping up because you're feeling the weight of expectation too hard.

Truth is, most people will appreciate the heads-up far more than if you hadn't. But, if someone complains after you tell them that? Screw 'em. People with that attitude aren't worth getting "approval" from. People who respect you, on the other hand, might very well become your best friends for the action to come.