I actually have a tougher time learning roles on dps. I won't know if there's a mob with kill priority, like hornets with surprise spike damage abilities, or what abilities should be CC'd when applicable. Not to mention I have to fumble with unfamiliar mechanics while maintaining my rotation and avoiding tunnel vision when things get hectic.

Any time I heal, I know i have to survive, and keep people healed, which is much easier for me since I know the sch and whm toolkits inside and out. Just get in there neck deep with whatever you have fun with, tell people you're new, and learn from your mistakes and advice from the vets. Don't expect a perfect run, but get stoked when you have one!