I am a student of commerce. Am I eligible to do BCA after graduation?

Yes, sure BCA can be done even after graduating from any of the streams be it Science, commerce or arts.

Yes, commerce students too are eligible for getting admission into BCA. The eligibility criteria for admission into BCA is that a candidate must have scored at least 45% in their +2. If you can satisfy this criteria, then you can easily pursue BCA without any problem.

Yes, why not? BCA can be done after graduating from any of the streams be it science commerce or arts. Good luck.