I have worked in the industry a good number of years and I can tell you that the vast majority of photographers, fashion or otherwise, have not taken any photography classes. They have just picked up a camera and experimented. You do, however, need money to get the equipment. If you're setting up a business you may be able to get a business loan for the kit but you'll need a good business plan to show the bank.
The most important quality for a fashion photographer is to be extroverted and be able to deal with people well. You need a good eye for fashion, composition, and lighting.