MBA/PGDM

There are multiple functional specializations in MBA such as Finance, Marketing, Human Resources, IT, SCM, Logistics, Operations, Systems, General Management or sector specific specializations like Travel & Transportation, Telecommunications, Healthcare, Banking, Insurance, etc. One must chose MBA specialization based on his or her interests, educational background, prior job experience and personality, skills and competencies.
Marketing is suitable for extroverts. If you have good interpersonal skills, sales aptitude, leadership qualities, good communication skills and have entrepreneurial attitude then you must go for Marketing. Individuals with good numerical ability can do very well in the field of finance particularly investment banking. If you good at number crunching, have superior numerical ability, good data interpretation aptitude, problem solving and creative thinking and you are also a strategic thinker then you must opt for MBA Finance. People with social skills and empathy are suitable for HR. To be become good HR manager you require skills such as organising capability, dealing with grey areas, Good communication and negotiations skills, capability to handle changes, capacity to handle conflicts etc
As per current market trends and available data maximum job opportunities are for Marketing professionals. Most of CEO and CEOs of large corporations are Sales and Marketing professionals. You are recommended to op for Marketing specialization.
As per Indian market trend analysis MBA Finance is the second best career choice of both MBA students and recruiter after MBA Marketing.

Hello Nikhil,
You have got enough time to prepare for CAT & GMAT.If you want to get into IIMs, one thing you can do is practice with complete dedication. Know your weak areas and practice more n more. It is very essential to understand time management. For that , make practice papers with your timer on.
and
If you want to do MBA from outside India, CAT isn't going to be useful. However, not all MBA programs require GMAT. Some are fine with GRE. I've heard some MBA programs don't even require an entrance test if you satisfy some other requirements such as CFA Level 3 cleared. Also, all MBA programmes outside India require at least two years of experience.
Good luck!