Hello Soha, 

Yes, definitely you can register yourself for the AIIMS PG 2019 july session now. 

As per the schedule, the AIIMS PG Exam 2019 will be held on May 5. The entrance test for MD/MS will consist of multiple choice questions covering all the subjects taught at MBBS level

The entrance test for MDS will consist of multiple choice questions covering all the subjects taught at BDS level.

And eligibility is that student must have qualified and possess MBBS degree for MD/MS and BDS degree for MDS courses of a University recognized by the Medical Council of India/Dental Council of India.

Hope this information is helpful. All the best.