Hi, You can apply in BMS after 12th and there is usually an entrance exam for it in Delhi university.
Scope is definitely good and the audience to take admission is also decent.

You can even check the complete BMS eligibility here:
DU BMS Eligibility Criteria

Scope: It will help you to develop managerial and leadership skills that you require in order to survive in a global organization and even if you plan to open your venture.
But again out of BBA and BMS I will suggest you BBA.
Incase you plan to do MBA after BBA then you can seek settlement.

Good Luck.