Will I be okay as a newb tank?

[Broor]

As long as you're keeping aggro, you're fine. Just try to rustle up a decent weapon, save all the money you can for bronze/banded, and spam flash of light once you hit level 9 and you'll be a better aggro machine than a twinked warrior.
Edit: But if you want the twink experience for melee/tank, roll a priest first and get some money saved up to spend on your eventual character-