Class 12-arts

Yes, students from every stream can pursue BCA even if you haven't studied Maths or computer Science in your +2. The eligibility criteria is different for universities, but many of them will provide you admission for BCA. Don't worry, if you don't have any experience in programming, you'll still be able to do good if you've interest in programming. Without the interest in programming, BCA will become very difficult for you to cope-up with. If you want to learn programming languages which you will be studying in your BCA course then you can check out this app "BCA - Course Programming" which is specially designed and developed for BCA students and is available on Google Play Store. It has programs and assignments of languages like C, C+ and Java with their outputs. You'll be studying these languages in your 3 years of BCA.

I don't think you'll be able to get admission into JNU after scoring 70%. Many government colleges don't offer courses like BCA. You can try to get admission from other universities or colleges for BCA. There are many universities in Delhi which will provide admission to arts stream students for BCA. If you want to learn programming languages which you will be studying in your BCA course then you can check out this app "BCA - Course Programming" which is specially designed and developed for BCA students and is available on Google Play Store. It has programs and assignments of languages like C, C+ and Java with their outputs. You'll be studying these languages in your 3 years of BCA. https://play.google.com/store/apps/details?id=technark.bca_courprogramming.