Exam

Hello,
According to exam guidelines, candidates who have passed Masters degree or enrolled in the post-graduation course are only eligible for the UGC NET exam. As you said, you have qualified graduation degree so, to apply for the NTA NET firstly you have to enrolled in the post-graduation course. To become eligible for NTA NET 2019, you have to score minimum 55% (For General) or 50% (For OBC/SC/ST/PwD/Transgenders) aggregate marks in Masters degree. You have to fulfill the age criteria also, appear for the UGC NET exam which is as follow
For JRF - 30 Years maximum age limit. 5 years age relaxation provide to the reserved categories. For Assistant Professor - Age limit is not applicable. You can apply for lectureship whenever you want.

For pursuing MBA, you need to ensure that you have scored minimum 50% marks at graduation level as it's the qualifying range for MBA admission. You are also required to clear CAT with a high percentile score to get admission into a good institute. An MBA can help you sharpen your skills in business management and thus assist you in the professional career. However keeping you interest areas in mind you need to decide what you need to do from a career perspective. The chances of doing well in the career of one's interest areas are much higher. In case digital marketing interests you then you can pursue MBA in marketing and pursue a certification in digital marketing as it will help you on the career front.