Hello dear..College is never good or bad..its on you , how you make it.Anyways .You didn't mentioned from where you want to pursue your Graduation,  but as I can see you are from Delhi , I am enlisting some  top College for B.Sc mathematics in Delhi.

Hans Raj College

Ramjas College

Miranda House College

Gargi College

Hindu College

Acharya Nerendra Dev College

Deen Dayal Upadhyaya College

Sri Tegh Bahadur Khalsa College

Jamia Milia Islamia College

Delhi University

Jesus And Mary College

Maharaja Agrasen College

Kamla Nehru College

Daulat RAM College

Deshbandhu College

Kirorimal College 

These are few top Colleges for B.Sc Maths in Delhi.There are number of Colleges In NCR as well. In some Colleges or Universities admission is done on merit whearas some Colleges/Universities demand for entrance exam. To apply for admission students have to fill online application form available on universities/College's official page 

Good luck