Hello. Considering you have a partial drop after 12th , admitted to first year basic science courses like BSCs. Then definitely you can give KVPY SB stream test.

Considering your Mark and aggregate, you can attend this exam. Because the eligibility states that being in 1st year of any undergraduate program must have secured a minimum of 60%( 50% for SC/ST/PWD)  Mark's in aggregate in science subjects ( Physics/ Chemistry/ Biology/ Maths) in the 12th std board examination. And which you have already. So go ahead.

Hope that helps!