You didn't mention field in which you want to do BSc. Please mention it. Otherwise, you are eligible to apply for BSc degrees in any of courses before 7th of June. Visit following link to apply for Delhi University BSc 2018.
https://ug.du.ac.in/app2k18/

Hello dear,
All things are based upon cutoff...
It depends on which stream you had in school. If I presume you had Arts/Humanities in 12th, then you can get a number of good colleges in Delhi University. Though you do not apply for these colleges directly, you fill the application online on the website of the University, and as the cutoffs are released, you choose which college you want to go to. Once that is decided, print out the application and go to the college with all your documents to take admission.

Remember, you may not necessarily make the cut in the first cutoff itself. For many colleges, the cutoffs begin very high, and then they start dropping low. With a score of 85% (considering thats your Best-of-Four from Arts and without any deductions), youll make the cut for a bunch of good colleges.

Good luck.