Well I would think it would be difficult for someone to try to get into the fashion designing without any formal training. There are schools out there such as FIDM/The Fashion Institute of Design...
you can go to any school but the one I'm going to be attending is the art institute. there are many all around the U.S but the one I'm going to is in San Francisco.
Usually it's about 2 to 4 years depending on if you want to get an AA degree only or if you want to continue for a BA Degree.You can even choose to go to school for only 9...