If you are new, you should play all of the classes, but you should get used to playing Soldier first.
DO NOT MAIN PYRO. People will tell you to play Pyro because it's easy. Do not do it. If you learn to play TF2 by playing Pyro, you will learn the game the wrong way, and you will learn Pyro the wrong way. The reason a lot of people say that playing Pyro is easy is because he has a good ratio of speed to health to DPS, and people just use him to charge directly at an enemy while holding down the fire button. This tactic does get some kills, but it only works if you have your team behind you, so it's pointless to just do it constantly. The Pyro is about zoning in the middle of a firefight and clearing enemies out of constricted spaces.
When you do play Pyro--and you should play all of the classes--don't just mindlessly charge at the enemy. Try to get close without being conspicuous, and be aware of your airblast, especially when there aren't any enemies within burning distance. And don't play too aggressively--the Pyro isn't necessarily about killing enemies. He's about punishing them.
DO NOT MAIN PYRO. People will tell you to play Pyro because it's easy. Do not do it. If you learn to play TF2 by playing Pyro, you will learn the game the wrong way, and you will learn Pyro the wrong way. The reason a lot of people say that playing Pyro is easy is because he has a good ratio of speed to health to DPS, and people just use him to charge directly at an enemy while holding down the fire button. This tactic does get some kills, but it only works if you have your team behind you, so it's pointless to just do it constantly. The Pyro is about zoning in the middle of a firefight and clearing enemies out of constricted spaces.
When you do play Pyro--and you should play all of the classes--don't just mindlessly charge at the enemy. Try to get close without being conspicuous, and be aware of your airblast, especially when there aren't any enemies within burning distance. And don't play too aggressively--the Pyro isn't necessarily about killing enemies. He's about punishing them.