给沉默是金。

1) Changing field is kind of normal. People do that a lot. However, there is a something behind MBA or management degree you don't see or I should say most of people don't see. Those who succeeded after MBA are based on their previous experience in this field. There is no way you'll become a manager when you are fresh out of school and know nothing about a certain field.
2) Experience first, degree is a plus. Especially in the downtime people respect your experience in a field more than the degree you have. Actually, it is the case. A diploma is only a ticket for you to ride on the bus. But if you have never driven a bus, are you sure you want to get behind that wheel?
3) It's OK to change field, but then you need to start from the scratch/beginning after you graduated. Be prepared for that, don't expect to get an important position once you get your degree. Yes, management related degree will help but you need to get experience first. Wish you luck.