Hi
We understand your concern. The eligibility criteria for getting admission in bsc course in jai narain pg college states that a candidate should have passed[10+2] exam conducted by the CBSE / higher secondary school (HSE) or any of its state equivalents with a minimum aggregate of 50% marks overall along with Physics, Chemistry, and Mathematics as mandatory subjects from any recognizeduniversity. 5% relaxation of marks is available for SC / ST candidates.

The admission procedure takes place on the basis of merit.  according to the guidelines of the institute, it doesn't state any concern for such cases. So, you can fill in the admission form, but preference of selection might be given to a student having appeared for 10+2 this year.
But for now, you should apply for admissions
Hope this helps!!!