It all depends on where you want to see yourself in the future. If you like computer, websites, mobile applications, etc. and want to build those, then you should go for a BCA. If you like to study a lot, understand every theorem by heart and are good in academics, then you should go for BSc. Both are good fields and both have scope. But after doing BCA you will most probably get work in private sector. After BSc, you may do MSc and then you may carry research or may do a job as a professor in some college.

BCA Totally depends on what you want to take up in B.Sc. 

BCA has a better scope if you want to go for web development and industrial jobs. B.Sc. is more inclined towards research and analytics. Choose what you want to do.

Both have their respective scope. BCA is for for students who are interested in Computer Science and programming whereas BSc forms the basis of science and comprises of the subjects like physics, chemistry, biology, zoology and mathematics.

So you will have to decide your area of interest and decide wisely.

Good Luck.