since I had no idea of filling multiple college options while registering for BMS in DU. will it affect my admission chances.

Hey,

The preference order once submitted cannot be altered once the payment of fee is exercised. The allotment of courses and colleges will be based on the rank secured by applicants and their order of preference of course and college subject to the availability of seats in the respective institutions. The seats available in each course and college in each category will be allotted to the applicants in order of their obtained ranks and preferences until all seats in the particular college-course are filled.

As per DU JAT selection procedure 2019, the allotment of course/college will be done by Delhi University based on the rank secured by the applicant and his/her order of preference of course and college subject to the availability of seats. No alteration will be entertained at any stage of admission.

For more details  regarding it visit the following website below -

https://bschool.careers360.com/articles/du-jat-selection-procedure

Hope this helps.