Getting into NIFT has nothing to do with your boards % .It is hardly 50–60% that is really a low percentage.The main thing to focus on is your creativity level , decent drawing and fluency of speaking english. Your 12th board marks doesn't affect your admission in NIFT.
Eligibility criteria:

Council for Indian School of Certificate Examination, New Delhi.
or

Certificate Education (GCE) Examination (London/Cambridge/Sri-Lanka) at the Advanced (A) level/ International Baccalaureate (IB).
or

Public School/Board/University Examination in India or in Foreign countries recognized by the Association of Indian Universities as equivalent to 10+2 system.
or

A pass grade in the Senior Secondary School Examination conducted by the National Open School with a minimum of five subjects.

Hello Monu

National Institute of Fashion Technology (NIFT) conducts an entrance exam for admission to B.F Tech and B.Des programmes. 
According to the NIFT Eligibility Criteria, aspirants must have cleared the +2 level examination in the 10+2 pattern of examination of any recognized Central/State Board of Secondary Examination.

You can go through the link below and check the detailed eligibility criteria

 https://design.careers360.com/articles/nift-eligibility-criteria

Do let me know if you have any other query.

Good Luck!