First of all let me appreciate your concern. It is a dilema that every commerce graduate go through when he/she is planning to do MBA.
Having couple of year work ex (in the field that you will be pursuing your Masters) before joinin a B school is definitely a added advantage.
On the other hand if you join immediately after your graduation it would be easier for you to continue your studies in the same flow.
From my personal experience, let me tell you that it is not easy to concentrate on studies after some years of work. But if you think that you can study after a couple of years, go for it. Nothing like it.
