I had done my graduation in commerce but am more interested in radio jockey and even looking for a career in RJ, what should I do?

See, follow your dreams and make a dare move. If you are serious in RJ it is a good field. But think a minute before taking a step in RJ and have a back up plan and see are you really capable to do it, if yes, proceed on to RJ rather than commerce or else go to commerce.

Yes, you can join, but you should have a talking skill and presence of mind and more over you may graduate in any field. All the best for your career.