Biblically, the answer of how old the Earth is, isn't answered outright if I'm not mistaken but a lot of Christians follow that belief. At the end of the day, those details don't matter. Those are arguments that people get into to start an argument and they get nowhere. Someone once told me this, and it's definitely true, no one has ever been saved by apologetics.
For my part, I was like many of you. I clowned Christians, hated everything they were about. The Gospel was something that sounded like it could be good for other people, but not me. My life has definitely been a mostly miserable one, but I'll never forget once that a family friend told me about her life and she was well into her 70's. She told me that the best thing she'd done in her entire life was giving her heart to Christ.
I understand how most of you feel and why you would hate a thread like this. Chances are, it will have mostly no effect on your lives. All I can really share with you is that for as messed up as my life was, the most real and true happiness I've known in my life is due to my relationship with Christ.