Hey rajesh.!
Interior designing is a good choice of yours according to developed era. In my opinion,you should go for degree instead of diploma. As you told both degree and diploma are for equal tenure so why to sail in pond if river is available.
All i want to express is that degree offers a wide knowledge and factual information regarding a course. If you are learning interior designing for hobby or interest or other reasons then you can go for diploma but if it's your passion and career choice, go for degree.
Also, if you will go for diploma you have to do graduation also at some point of time in life which will disturb your focus on interior designing. Kindly check the fees structure too of both and then choose wisely what is beneficial in your circumstances
Hope it helps

Hello aspirant

If you have completed your intermediate,them Bachelor In Interior Design will be a good option. This will give you a bachelor degree, where as Diploma in interior design is also good but not a good choice after 12th.

Hope you get my point...

Thanks!!