Hy there ,

See you marks in BBA are less as compared to the eligibility criteria for BBA admission.
The eligibility criteria says that a candidate applying for BBA should have a minimum of 50 percentage aggregate marks..

However , admission in bba also  depends in which college/university you seek take admission in. Every institute has different criteria for giving admission.  Some check the 12th marks i.e merit based while some conduct  entrance exam for admissions in BBA .And then based on your score, youll be given admission.

So your grades in 12th might not be of much importance.
But some reputed colleges in India conduct both Entrance exam and a Personal Interview.
For e.g. Christ University, Bangalore and Delhi University.
So if you grades are less, then it might leave a negative impact on the interviewer. This would reduce your chances of selection.
Moreover, grades are not just important for BBA admissions but also for MBA and securing a good job in future. A good score in 12th will help you crack interviews and will have a positive impact on your resume.

I hope it might be helpful.