Should I wait for one year and try for an MBA or join PUMBA as a fresher?

If you are a fresher, I advise you to give it another go and take the CAT, XAT, and other management tests the following year. A high CAT percentile will lead to various opportunities for you. 

It can be worthwhile to wait and reapply if you are convinced that you can raise your profile during the following year and get accepted into a more prestigious MBA program that better fits your professional objectives. 

On the other hand, entering PUMBA might be a good choice right now if you want to start your career early and obtain job experience. Executive MBA programs can be pursued at a later time in your career.