Interior Design

You can opt for a Diploma course. Kindly visit the link mentioned below:
https://goo.gl/FIKoG1

It would be great if you can complete your HSC and then do a degree course as a degree is always preferred over Diploma. Till then, you may take up other certificate courses in designing field.

Make sure you are good with drawing or designs as that is the first and foremost thing to be taken into consideration when you are talking about design field. Get into the field only when you look yourself as a great interior designer in future or else go for any IT related course if you are good with computers.

1. National Institute of Design (NID)
2. Sai School of Interior Design
3. Sir JJ School of Art
4. Arch Academy of Design
5. IILM School of Design
6. Vogue Institute of Fashion Technology
7. CEPT University
8. Shri Devi College of Interior Designing
9. Exterior Interiors Pvt. Ltd
10. College of Architecture

Both the fields are good but architecture includes interior designing. Architecture is a professional course whereas interior designing is a certificate course.
If you don't want to study for 5-6 years then go for interior designing otherwise architecture is the best.
Now it depends on your choice. Whatever decision you will take just enquire properly and take a rational decision.
All the best and have a great career ahead.
Please feel free to revert.

It depends on your interest, but B.Arch has a wide scope.

Hotel management is a good option.

Yes, you can and there are many colleges for the same. I am listing few of the best colleges there:
Sir JJ School of Art
Rachna Sansad School of Design
Pearl Academy
Raffles Design International
Aditya College Of Design Studios and many more.