Hi icandothis3,
Congrats on the admit and on passing the first exam. Everything gets easier after the first one (Tried some engineering certifications of similar style)
While I can't speak of all schools, I know Duke allows program deferrals but generally has a rather strict policy. Here's exactly how it reads... "Deferrals are granted only in the case of significant, unanticipated, and unavoidable personal emergency. An admitted student may be deferred up to, but not beyond, the same term in the succeeding year." So whenever you request a deferral they typically expect an emergency of some sort as your reason of deferral. It's actually likely that they will contact you back with things like "Why not defer your CPA instead?" So you better have a lot stronger case than just wanting to finish CPA first.
My suggestion is to build a strong case where you link your work experience with an "absolute" need for CPA, without which you will not get the right experience for the class. Even more so, you could link your next promotion (Since you'll be still working and if it were somehow true) to getting a CPA. In all cases, you will mostly likey be given the deferral if you showed that there is an evident danger, either to your personal life or career, associated with not deferring the program. After all, there are many students who would want to ensure their seats into the school and then go back to continue working and adding some more money and experience.
Alternatively, if you weren't granted the program deferral, you might want to finish two exams first before the degree, finish your MBA, and then go back to the remaining two after settling down for some while. This way, you would leave some time between the two accomplishments which I think will help you more than finishing CPA and MBA together. Sometimes you need to startigically place them along to get the best reflection on your career.
All the best convincing the admission folks.