B.Sc

Every applicant who intends to take admission in a course is required to get his/her name registered on the website of C.C.S.University, Meerut for which registration fee is charged. Use this link for completing the process of registration http://www.ccsuniversity.ac.in/ccsu/index.php
Eligibility criteria : B.Sc. Degree (with the concerned subject as one of the main subjects) with 45% marks in aggregate and 50% marks in the subject.
Admission criteria : On Merit based.
So from above if you have completed you B.Sc with Math as major subject, Than can be eligible. Please see information brochure of CCSU for more details http://www.ccsuniversity.ac.in/ccsu/reg-course.php#

The asked College does not have the own official website. Hence, the general eligibility criteria of B.Sc Hons Biochemistry for the University of Delhi is given below.
B.Sc (Hons.) Biochemistry is a three-year undergraduate program with a specialization in the inter-disciplinary domain of biochemistry. An aggregate of 60% or more marks at 12th level in Chemistry, Biology/ Biochemistry/ Biotechnology and Mathematics/Physics with 50% or more marks in English
Apart from the above-mentioned eligibility criteria, various colleges and institutes may have their own additional criteria that students would have to satisfy in order to take admission.

B.Des eligibility criteria of NIFT is given below.
1. Qualifying Age: Maximum age should be 23 years as on 1st October, 2019. The upper age limit may be relaxed by a period of 5 (five) years for candidates of Scheduled Caste/Scheduled Tribe/ Person with Disability (PWD) categories.
2. Educational qualification for Bachelor of Design (B.Des) Programmes (Fashion Design / Leather Design / Accessory Design / Textile Design / Knitwear Design / Fashion Communication) : The +2 level examination in the 10+2 pattern of examination of any recognized Central/State Board of Secondary Examination, such as Central Board of Secondary Education / State Board New Delhi, and Council for Indian School of Certificate Examination, New Delhi.
So from above age criteria is very important. The Gap of 5 years after 12th is not a big issue because you have completed your graduation during this period. So you can be eligible if meeting the age criteria as above.
Further you are also eligible for M.Des course of NIFT because there is no age restriction for M.Des course. While the eligibility criteria is Graduation in any discipline. The admission in M.Des are also done through NIFT entrance exam.