I'm a WoW addict. I have five L70 toons and I've leveled every other class to at least L35. Warrior is a poor choice for a first toon to get acquainted with the game. The two easiest classes to start with would be a Hunter or a Warlock. The downside that both that classes are very popular so getting groups will be more difficult than if you chose a tank or healing class. For me warrior, rogue and mage were the hardest classes to start up and level as a solo player. Most classes don't really start to become fun or shine until you hit L35 to 40.

Blizzard just lowered the level for getting a mount so traveling gets alot easier once you hit L30.

If tanking is what you want to do then expect a bumpy road that will require you to learn more about the mobs, instances and all the other classes than any other role you could pick in the game. You'll be expected to mark mobs, orchestrate the pulls and hold aggro.

If you have any questions feel free to ask either in this thread or via PM. I've been playing almost since WoW launched and have experience up to T5 raiding(I quit raiding once I hit that level and my guilds kept imploding).