I don't know whether it will depend on your case. Because I have seen people who had to wait after the eligibility interview to get a decision. But always be prepared before going. Know your case inside out. They told me that they have already referred my case to the IRB. And everything was ready; all the papers when I got in for the interview session. They only told me that I will hear from IRB now and that was it. They didn't specify a date. But did mention that they will send a notice to appear for the hearing before at least 20 days of the hearing. Don't worry brother, the interview will be alright. Just prepare yourself and go. I wish you the best of luck and God bless. Take care.