CBSE 12th

Hi Rishav,
You have to go to the college the improvement exam forms from offices of the education boards. For CBSE, the forms for improvement exam are made available from July of every year. You can get their forms from syndicate bank branches in CBSE Regional offices. Check here for more details:
http://www.improvementexam.com/what-is-cbse-improvement-exam/

Hi Aparna,
Advanced (A) Level - (London / Cambridge / Sri Lanka) General Certificate Education is considered for IIT JEE Mains exams. If you have completed from one of these boards there is no need to enroll into a 10+2 program again.

For IGNOU affiliated BHM course, age limit is 25. You just have to clear entrance test for that and if you want to do it from any another private college, you can also go for that.

Hi Vishal,
There will be a number of private universities where you can check for your bachelor's degree. Many universities will also have a defence quota. If you are not interested in full time degree you may check for distance or part time degrees.

Hi Ashutosh,
Typically students pursue bachelor's degree after HSC. Many also pursue diploma programs. You may decide basis your education background/stream/subjects and interests.

Hi Shelley,
The best course varies from person to person. You should also mention your stream for best possible options.

Hi Chandrakant,
You have to check NIOS or open schooling for the same. Universities will offer courses from bachelor degree onwards. For distance education after your 10+2 you may consider Indira Gandhi National Open University (IGNOU), Yashwantrao C Maharashtra Open University (YCMOU), Maulana Azad National Urdu University, Dr. B R Ambedkar Open University, etc. Also check UGC website for a list of approved distance education universities in India.

Hi Pratham,
You may compare the various programs and roles in the sectors you are interested in and decide accordingly. Talking about defence you have to decide if you want to join Indian Army or Indian Navy or Indian Air Force. You must also take the UPSC, SSC or CDSE. To pursue MBA you have to take your CAT/CMAT/XAT, etc. Career roles vary accordingly. You must know what you want and decide.

Hi Abhay,
There are many roles and options in aviation field. Please specify your requirements in details for better options. If you want to be a pilot, you may refer to this article:
https://www.shiksha.com/aviation/flying-pilot-training/articles/career-in-commercial-flying-all-you-need-to-know-blogId-13472#blogCommentSection

Hi Parvinder,
You may check the link here, all colleges mentioned are good ones. You may filter out as per your location, fees, etc.
https://www.shiksha.com/bba-chp9