CBSE 12th

AFCAT (Air Force Common Admission Test) is an entrance test for aspirants willing to join Indian Air Force as Commissioned Officer in Flying, Ground Duty (Technical) and Ground Duty (Non-Technical). The examination is conducted twice a year in February and August. The test is conducted all across India by the Indian Air Force. AFCAT Eligibility for Flying Duty: - Minimum of 60% marks each in Maths and Physics at 10+2 level.
Graduation with minimum three years degree course in any discipline from a recognized University with a minimum of 60% marks or equivalent.
Or, BE/B.Tech degree (Four years course) from a recognized University with a minimum of 60% marks or equivalent. So, you are not eligible for AFCAT. Now, for Indian Navy the requirement is class 12th with PCM, if you wants to go through the NDA (National Defence Academy) entrance exam. So, class 12th commerce students are not eligible here.

As you said you are a commerce student and you have keen interest in Maths, the best career option for you can be Actuarial Science. Actuarial Science is the discipline that applies mathematical and statistical methods to assess risk in insurance, finance and other industries and professions. This is the highest paid profession in the world. You are eligible for this course if you have completed 18 years of age and have secured minimum 85% marks in mathematics in class 12th. Besides Actuarial Science, you can opt for CA (Chartered Accountany) course, as you like accountancy as a subject. For CA, you have to clear CPT exam after 12th. It is 4 hrs exam and has 4 subjects: Accounts, Maths, Law and Economics. Questions asked in this exam are of multiple choice. You have to secure at least 60% marks in aggregate and 30% marks in individual subjects to pass this exam.
There are a plenty of other career options also:
1. Cost and Management Accountancy(CMA/CWA)
2. Company Secretary (CS)
3. Chartered Financial Analyst (CFA)
4. Certified Financial Planner (CFP)
5. LLB
6. BBA/MBA