First you need to honestly know if its something your good at. Some people no matter how hard they try just can't read horses which is a big part of training. Then decide if it is a passion, yes= you can make a living at it but aren't going to have a whole lot of extras[money,time,holidays] Check around if an average mortgage is $1000 and trainers are only getting $500 you will be starting in the hole and will need a back-up source. Remember-Insurance[barn,farm,house,liability,medical,vehicle] Electric,Feeds,Vets,Farriers...
A really good way to start is either as a working student or an apprentice and a business based degree can't hurt. As far as being a top notch trainer when you are starting out contact that top notch the one you already worked/apprenticed for. He doesn't/won't take green horses and if your really good at doing the greenies=great working relationship. He trusts horses coming from your barn, he already has a waiting list, everyone stays happy and full of clients and there is no direct competition.