on young/old earth...

One can easily read the Bible to be "young earth". In fact, that's the easiest way for Western contemporaries to read it. But as with its Bible bookend, the book of Revelation, reading it "straight up" may not be the proper approach. (I like what Nelson Kraybill said about Revelation in this regard: trying to read Revelation "literally" [whatever that term means] is akin to reading the phone book like a novel.)

I have a much longer post on this. But here a few, brief/summary thoughts on addressing the possibility of an "old earth", biblically...

1.) On "apparent age"-- the idea that God created everything in a way that necessarily looked like it was more than a minute "old"-- it's interesting to note that Jesus' first miracle (recorded in John 2, just after the reference to Jesus as deity and Creator in John 1) is to turn water into wine, creating something with apparent age.

2.) For those who want to stay "more literal"...
a.) Habakkuk 3:6 and II Peter 3:5 seem to imply an old earth (Is the earth 120 hours older than Adam?); 
b.) Adam had a *really* busy "sixth day"; and
c.) Recognize that the Hebrew word for "day" is used a half-dozen ways just in the first chapter plus of Genesis.

3.) For those who are willing to go "less literal"...
a.) "literary theories" on various ways to read Genesis 1-11 more broadly (I'd recommend Jewish scholar Nahum Sarna's Understanding Genesis here); and
b.) John Walton on the connection of the Creation story in Genesis 1 to the Temple. (He's interviewed in CT on this, but his book is good-- here's my blog post on it.) 

4.) A closing thought from science: In The Science of God, Gerald Schroeder lays out why time will look different from earth vs. the center of the universe in a way that accommodates both views. (Russ Humphreys seems to make similar case here.) The result is a both/and theory in which Creation occurred over six days from a cosmic perspective and the universe is 15.75 billion years old from earth’s perspective. This lines up with OE science, the manner in which light travels, and the relativity of time. 

Bottom line: The age of the Earth should not be a stumbling block for those considering entry into the goodness of God's Kingdom. 

P.S. Leon Kass taught Genesis at the University of Chicago for decades as a "great books" course and his amazing book, The Beginning of Wisdom, came out of those efforts. If you're doing a study of Genesis and can handle a big book, it's a must read.