Hello again courtney. I am not at all surprised that your sister told you not to come here. Like I said before, they want to control the kind of information you recieve. They do not want you to get both sides of the story, they want you only to get their side of the story. They will do everything they can to convince you that you shouldn't listen to anyone but them, and that you should only be studying their material and not paying attention to what anyone else says about their teachings. But does that sound like a balanced view? Does that sound like a reasonable way to get accurate knowledge? Or does that sound like a pushy salesmen trying to convince you that he's the only person you can listen to?
I cannot emphasize enough how important it is to go there, and just read on different topics. Compare it to what they are teaching you, and ask the people studying with you about it. In fact, take them there and have them go over the information with you. Don't let them just say "don't listen to that, don't go there, don't pay attention to that, it's just lies, it's not important." If you read something on that site that makes you have questions about what they are teaching you, force them to answer those questions.
They are trying to pressure you into joining the group by making you exclude everything that they don't want you to see, or everyone they don't want you to talk to. They don't want to reason with you or teach you, they want you to just repeat after them, say whatever they say is true. You aren't going to learn the bible from them, you are going to learn to repeat what they say about the bible.