Yes, you can enroll at NIFT after your 12th, but there are some criteria for eligibility.
For the B.Des. program:
You must have passed the 12th from a recognized institution in any stream.
While for B.F.Tech Program:
You must pass 12th from a recognized institution with Physics, Chemistry, & Mathematics as chosen subjects
And Of course, you must clear the NIFT Entrance Exam.
You can enroll to NIFT after the 12th if you meet the requirements listed above.