I have 45% PCM aggregate. Which is suitable for me: BBA or BCA? And which college I can get?

Difficult as your percentage is low. Look for private colleges and sit for interviews.

Choose your career as per your interest so that you don't feel difficulty. As per my point of view, you can go for BCA which has a vast and a higher opportunity for future. All the best for your future. You can select any college as per your preference.