Hii Bhawna,

Yes, you can pursue BCA after being an arts student. Note that not every university will provide you admission but majority of the universities will get you an admission into BCA without any problem. The general eligibility criteria for getting admission into BCA is that a candidate must score atleast 45-50% in their +2. It'll be highly beneficial for you if you have studied maths and computer science in your +2, because you'll be studying these two subjects in your BCA.

ALL THE BEST!!