Certification

You will get MMS degree from Mumbai University. Whether it is the right place for you or not, depends on your score, and which other colleges are you getting admission in. If you were getting in top 4 colleges like JBIMS, Sydenham, K.J or Welingkar then definitely those are better places than ADMI. But if you dont want to repeat the CET or you want to pursue MMS this year itself, then ADMI isnt a bad choice either.
The placements here generally offer a average package of 4.5 L pa. The faculty is good and visiting faculties are a class apart. The advantage is you get to be on Mumbai University campus where you can attend many events and conferences organised by other departments like economics, statistics, languages and get a better exposure and networking opportunities. The disadvantages are being a government institute the infrastructure or the overall pace of getting things done is a little slow. So choose wisely.

You may consider following certification options to become BA:
(a) International Institute of Business Analysis (IIBA) is the recognized, non-profit association for business analysis professionals around the world. In order to have BA career you may obtain professional certification such as Certified Business Analysis Professional (CBAP) or Certification of Competency in Business Analysis (CCBA). You may refer to https://www.iiba.org/ for further details.
(b) BCS, The Chartered Institute for IT, is well recognized organisation for global IT profession. BCS has different courses for new entrants to the business analysis profession through to senior BA professionals . You may refer to http://certifications.bcs.org/category/15680 for further details.

ERP is an abbreviation of enterprise resource planning and means the techniques and concepts for integrated management of businesses as a whole from the viewpoint of the effective use of management resources to improve the efficiency of enterprise management. ERP systems integrate all the functions and departments within an organization through a common information system.
Most common modules for the ERP system are finance, manufacturing, human resources, procurement, customer relationship management, etc. SAP is the world's largest selling enterprise resources planning (ERP) software system. For the implementation of SAP, you require ABAB developers and functional consultants. If you want to make your career in the technical, then you may learn ABAB and do certifications. In case you want to be a functional specialist, you can do one of more functional module certification. SAP professionals are paid above the normal developers and business analysts. With SAP certifications, you can join IT companies or IT department of a business enterprise.