M.A

If you have completed your BA from a UGC approved university then you can do MA in regular mode.

Please refer to the link provided below for details regarding admissions in MA programs from IGNOU. The eligibility criteria for this program is graduate in any discipline with any pass percentage in the UG course.
http://www.ignou.ac.in/ignou/studentzone/programmes/2

Keep an eye on the notification of the entrance exam and you will definitely find the syllabus for the concerned subject. Also, look at the past year question papers. They are really helpful.
The crowd in JNU is diversified and you will find someone alike, so don't worry. It has a good crowd. Comeon, so many people compete for such less seats, it has to be good.

Dear Tarun,
If you can afford to pursue it from some other university then it is advisable to pursue it from English and Foreign languages University (EFLU), Hyderabad. The admissions for distance mode are going on. For further details, kindly visit the below-mentioned link:
http://googleweblight.com/i?u=http://www.efluniversity.ac.in/&grqid=8cNiXU8x&hl=en-IN
I hope this would suffice. All the best and god bless you.

You don't have to pursue BA again as you have completed MA. You can pursue B.Ed and then clear, N-TET, NET, etc.

Yes, every PG courses requires a minimum percentage from UG course. Irrespective of which course you wish to choose.