For the date: I'm Simply looking at the creation its self. Gen 1:1 dose not say when. So by default , I look at the world around me. I'm also not a geologist, or familiar with the dating methods. So I'm going with what is the accepted consensus about the date for the earth .
I connect Genesis, with Peter , because of the other teachings that you have to be familiar with ( that I touched upon in my previous response ) if you want to get this , and where I'm pointing to, you have to be familiar with more scriptures about this then.
In the Bible there is something called, three ages. Phrases used like, foundations of the world, predestination ,and like I said already ages, and many other things .
Once you get a grasp of those scriptures, then this comes together . and you can maybe see better what I'm referring to. Why and showing you how it connects , and documenting that from scripture is not easy for me to do.
So I will try to respond in a week, as I study it closer, and take down notes . When I get a response together that is thorough . I'll post it here, or to my blog and send a link.