Awe, I remember my first tanking experience...I apologized the entire time about my incompetency. But to be honest, I was incredibly undergeared. In my opinion, tanking's fun 'cause everyone relies on you!
People can go ahead of you if they want but I've had my share of sassy (rightfully so) tanks who've told off DPS for going ahead of them and pulling monsters like a complete idiot.
It's fun being the "leader" of the group; people rely directly on you to keep from feeling the embrace of lady death.
I'd say, if you haven't tried tanking yet and you've been DPSing all game...you need to at least try. Tanking is fun...when you know what you're doing! Generally, people are more willing to accept your shortcomings if you're a tank (mostly 'cause they don't want to wait any longer for a DF).