I am interested in event management and banking. Which field should I choose after graduating?

You can opt for MBA in event management, if you want to study further about event management.

For event management, you can complete graduation and then join a good postgraduate institute offering event management course. Graduation in engineering/arts/commerce anything will do. For banking, it is better to opt for graduation in B.Com and then try for CA or exams like IBPS PO and SBI PO.