I made a deal with the agency to check in at 21. We met the man who were responsible for check in right before 21. I was informed that after 21, you are required to pay 30€. He showed us the place, and when he left at 21:05 I demanded 30€ from me. That was very disappointing to be honest.
The place is very nice and short to busses and shops. Very easy to get to the center of Rome. The apartment was high quality, and agency gave you a lot of useful information about Rome.
However some of the kitchen supplies were very dirty. That is the only negative comment for this apartment. I recommend!