It is more competitive with MS in taxation to go into tax, but not
necessarily the determining factor. Only big 4 will make you choose either
audit or tax at the beginning, they expect to train you from scratch as long
as they like you, so the degree doesn't matter much. It's mostly the soft
skills and personality you demonstrated during interview that matters.
Word of advise, if you don't like something, it's really hard to fake it and
show your passion toward it during the interview. A few questions and how
much you know about the career path and long term plan of such profession
will tell the interviewer exactly your attitude and how much homework and
research you have done.