Ok guys, update***
So I have been doing my homework, and been asking people around the internet here and there about this whole interview process.
So basically this is what goes on during the interview: You go in, show your ID and your notice you got in the mail. DO NOT take in your phone, as they will make you take it back to the car and this could make you late for your interview. You wait for a little while and they call you in. They make you swear that you will be telling the truth. They take you inside an office. They tell you it is just a procedure, something random. Then they ask everything about the I-821 D application (the 6 page one) Nothing about the I765 or i765WS (work permit) applications. While asking you, they are watching your every move, so if you do stuff like tilt your head (something that shows you are in doubt) they will ask you more about that question. They go over every single question, so you might want to take a look at that application question by question and make sure you know what you answered. No one should have a problem because you should know the questions since they are about your life. Of course never mention any details if they ask you how you got here. You can say you don't recall, you were little. Back to the interview, it is very brief, 15-20 minutes. The agents are not wearing a uniform, they are normal people.
After the agent is finished reviewing every question, he or she will tell you that you should receive a notice within the next 30 days. It actually takes 3 weeks. And this is it!
Extra: You might want to take more evidence in case they ask you, but this really hasn't happened to anyone. They do ask you if it's the same evidence as the one you provided. And they do not review it. But do take a copy of your whole packet and the originals just to be on the safe side
Good luck and be prepared!!! I know it is stressful and dreadful, but everything is looking great for us! Let's not panic!