For example, in most cases a degree will be necessary for being hired as a photojournalist. We might argue that it shouldn't be the case, and we can find examples where it wasn't the case, but that's where major news outlets look.
On the other hand, a degree doesn't matter at all for wedding/social. That doesn't mean business acumen is not essential to success. But most business degrees in 4 year collages are not oriented to the small entrepreneur.
Advertising has it's own requirements, with essentially an apprenticeship from what I understand. But others can weigh in.
So I think you need to give us a hint of what "going pro" means to you. Otherwise, you may get a lot of answers that are right for someone else but wrong for you.