IBD -> S&T post-MBA

I know this has been discussed extensively but wanted some perspective on IBD -> S&T a year into BB IBD Associate position post top MBA. Hours/culture of IBD don't bother me but I've come to realization that I'm more interested in Trading. Was in a non-finance trade prior to MBA so didn't know any better at the time of recruiting.

Questions for you all are: Is it almost impossible to switch without having to go back to school? Should I just suck it up and try to build a career in IBD at this point? If I have to go back to school, is it even worth it purely from opportunity cost perspective - S&T pay is about the same as IBD?