Maths Spl

You can surely pursue CS as it doesn't consist of hardcore mathematics. Yes, however, it is not exclusively maths but some or the other form of maths.
For instance, you can count accounting as a form of maths solely because it involves numbers, but the concepts and rules of accounting are by themselves independent and unique and are not mathematical.
On the other hand, advanced subjects like Costing and Financial Management are mathematical. However, be advised that these subjects make up hardly 20% of the total course and are not as focused on maths as the one's in CA or CMA.
CS moreover focuses on Company and corporate laws. It is moreover important to have a detailed knowledge of the theoretical part. Practical knowledge is important. However, a company secretary directly doesn't involve practically into accountancy work. He/she is an officer who has to keep a check and balance over the entire working of the company for efficient administration.
I hope this would suffice.

As a B.Sc student, you can apply to any MBA college provided you took the entrance exams like CAT, MAT and XAT and also qualify in the same with a good score so that you can apply for reputed colleges. You should also fulfil the minimum criteria like the percentage scored in UG. As a student who has completed his/her Bachelor's in science can apply for the MBA course. The first year has no specializations and has general management subjects. The second year has a specialization subject where you will have to choose between finance, marketing, international business and operations. Once you complete your first year, you will get a clear idea about the subjects and which field to specialize in according to your interest in that particular field. Do not choose a field depending on your graduation subject.