Many people, mostly friends and relatives approach me with this question. Its usually questions about the course options and future career prospects of interior designing and architecture.
First off all, to become a designer, the course is just an academic qualification that will enable you to enhance your capabilities as a designer. It will train you in the skills required to practice in the industry. However, before that, you need to understand what the profession is about and ensure if that is really what you want to do.
Visiting companies and firms or taking up short internships to understand the industry is a good start to exploring possibilities. You should approach career guidance counselors or converse with people in the field. Attending workshops and events can give you a first hand perspective of the field. All this research and experience will definitely give you an edge if you decide to pursue the course.
You can do a B.Arch, Bachelors in Architecture degree (3 to 5years) or a D.Arch, Diploma in Architecture Assistantship (2 to 3 years) or a Certificate course based on your level of interest. Diploma and Bachelors degrees have entrance exams for the admission process. NATA is a nationwide aptitude test for pursuing Bachelors degree apart from the common entrance exams.
Architecture and Interior Designing is a Practical Science. What you see on paper, the sketches digital images, drawings, etc are just one part of this industry. The real deal is how these are translated into reality.
All the best!