Design

Admission in B.Arch:
Candidates have to complete their 10+2 examination with mathematics and English as compulsory subjects & secure at least 50% marks in the examination.
Those candidates have 10+3 year Diploma in any stream, they can also apply for B.Arch programme.
Candidates can get admission in this programme through JEE Main, NATA.
Some private universities also conduct their own entrance test for admission in B.Arch such as BITSAT, SRMEEE, etc.
After completing your B.Arch course, you have a scope of higher study. You can apply for CEED and GATE.

Refer to the link below:
https://www.shiksha.com/design/communication-design/exams/nid-entrance-exam/syllabus

Refer to the link below:
https://www.shiksha.com/design/fashion-design/articles/top-design-entrance-exams-2017-conducted-in-india-blogId-11334

You can join interior design course for graduation.

CEPT is only for interior designing course.

Refer to the link below for admission procedure:
https://design.woxsen.edu.in/admissions/

No, no good college gives you admission after 10th.

The college does not disclose to others, so it is better that you check the same with the college itself.

Yes, you can surely pursue M.Des after completing the mechanical course. You should go with the full flow and don't settle anything less than NID. Start preparing for it from now on.

Please use the link provided below to access details regarding admissions in Nirmala Niketan College of Home Science for Diploma in interior designing. You can download their brochure which contains details regarding fee structure, important application dates, admission procedures to be followed, etc.
https://www.shiksha.com/design/interior-design/course/diploma-in-interior-designing-nirmala-niketan-college-of-home-science-marine-lines-mumbai-120209