If you've been around Christian circles much, which I assume you have been, there is a grand sentiment that conveys the idea that "We can't argue Sinners into heaven, God has to be the one to convince their hearts and lead them to himself." Are you familiar with this? You've probably heard it a thousand times. Well, the same goes the other direction. Until Christians are mentally in a place where they can hear logic and the actual real truth, and their hearts are in the right place, you might as well be talking to a brick wall.
So, I know it may be easier said than done, but seriously-- just quit going to those discussion boards. You're going to make yourself crazy for nothing.
I think you are still having a lot of angst about who you are and what you believe, especially knowing that you are still under the collective thumb of your family. My advice to you is to start looking internally at yourself and figure out what is important to you, both in a civic sense and a personal sense. Who are you, and what things do you want to stand for? Then start working on those things. The Christians on yahoo answers will take care of themselves, but they are not your problem!