There are many reasons one may choose a category to shoot in. Speed, types of guns, calibers of ammo, clothing, the character you are trying to mimic or become. #1 one thing to remember is be safe and have fun. #2 You can always change if you don't like it or don't feel comfortable.
With that being said I shoot Classic Cowboy and love it. Part of the game for me is dressing the part. Note I said for me it's not for everyone. And I enjoy shooting the 66 and the 73. And shooting duelist.
One thing I'm learning is that Classic Cowboy's and Cowgirl's will stick together and look out