Big 4 grad school decision advise

I recently accepted an internship offer from a Big 4 firm next summer. I originally thought I was going to get my masters in Accounting, thinking it would later help me transition into IB or related jobs. I already have 150 credit hours to qualify for the CPA exam, and for several reasons I am thinking about skipping grad school and taking the exam after my bachelor's. I'm really hoping to get a full-time offer from them after my internship, but they are obviously under the impression that I won't be available for another year. Does anyone know if the firms are lenient in this regard? I was also hoping to get advice regarding bringing this up to my manager.