Really, please, play dps or healer, something that doesn't have the responsability of being the party's head, learn your dungeon, and then go tank it.
I've helped new tanks who had never set foot in the dungeon and didn't know the strategy - it wasn't that hard. Anybody can explain mechanics and be the leader, it desn't have to fall on the tank at all costs.

I actually love explaning things to new tanks because as a whm I'm ignoring some mechanics that dps and tanks have to deal with - but this way I remember them all! It's quite fun. It's all a matter of communication.