Science

DoMS NIT Trichy is known for analytics and IT consultancy. However, it depends on your sole interest whether to choose a career in administration or technical side.

I would suggest that you complete your Bachelor's degree and then take up a job. This will help you get industry exposure and then if required you can opt for a Master's degree in a course relevant to your previous work experience. Only after you complete your Bachelor's degree, you could you think of settling down. You could also think of starting your own business, but that too requires a lot of work. There are very few shortcuts to settling down, so you should carve your own path to do so.

Yes, M.Sc in nursing will help you a lot. Go for it.

You need to complete UG and register for CAT exam.

In which field did you complete your B.Sc?

After completing B.Sc, you could apply to institutes offering courses in M.Sc. Please check the eligibility criteria and admission process of different institutes online. You can do this by downloading the admission brochure of different institutes. This should give you a fair idea of what is required of you to pursue M.Sc.

There are many institutes offering courses in astronomy and astrophysics in India and even outside India. Some of the good institutes are as follows:
1) Harvard-Smithsonian Center for Astrophysics
2) Indian Institute of Astrophysics
3) Institute for Astronomy and Astrophysics
4) Center of Astronomy (Heidelberg University)
5) Herzberg Institute of Astrophysics
These are only a few of the many institutes offering courses in Astronomy and Astrophysics. Check online for a more detailed list.

Job opportunities and careers available to you after completing graduation in B.Sc are as follows:
1) Medicine
2) Clinical psychologist
3) Neuro-physicist
4) Research scientist
5) Food scientist
M.Sc after B.Sc is a good combination and will open up many more avenues and career options.