Design

It all depends on what you are interested in, but according to me, designing is a good option. There are so many courses available in the designing field.

If you have already done graduation in design (B.Des), you should try to get in National Institute of Design (NID), they have 20 different streams in design. You can take the specialised course of your interest. There are several other Institutes for design in India like IDC, IDDC, CPDM, etc. And believe me to be a good designer, you don't necessarily have to be a good engineer, basic knowledge will also work.
For more details, kindly visit the link mentioned below:www.nid.edu
You should opt for M.Des abroad.

They are not three different streams. Automobile and product design are the sub-streams of industrial design. There are many sub-streams of ID like product design, textile design, ceramic and glass design, furniture and interior design, transportation and automobile design. For more details, kindly visit the link mentioned below:
www.nid.edu
All the best!

No. In order to pursue B.Des, you need to appear for the entrance exam of NIFT after completing class 12th.

There is no definition of NIFT. The full form of NIFT is National Institute of Fashion Design.

A degree course in interior designing is of 3 years duration. Yes, it is must to give intermediate exam for pursuing interior designing course from a good college.