Hello,
Management has major domains like Finance, Operations, Strategy, Marketing, Information Technology, Human Resource and other minor domains.
A Management course (MBA/IPM), which is all about business operations and people management.
So MBA is regardless of what you have done in your graduation, it about Time, Business and People which is everywhere.
Sure you can apply for CAT 2019, just make sure that if you wish to get admission after CAT 2019 score, you clear all your graduation formalities and receive the leaving certificate and all marksheets.
Hope this helps.
All the best!