In this letter I assume for the sake of argument that the Bible is in fact "God's Word." Even given this assumption, young earth creationists needlessly make their preferred interpretation of Genesis a hill to die on. And die on it they do.
The Answers in Genesis website (a young earth creationism site) says, "Of primary importance is the fact that evidence is always subject to interpretation by fallible people who do not possess all information."  AiG is referring to other fields of study, but this should apply equally to the study of Genesis. If you value the Bible as much as you claim, you certainly don’t want to misinterpret it.
You argue that the "days" in Genesis must be 24-hour days, which means god must have created the world in 144 hours, with a 24 hour break at the end. You say such things as, "God says he did it in 6 days, not thousands of years!" and "God created the world and everything in it in six 24-hour days just as the Bible tells us." Are the "days" really literal 24 hour periods of time? Could they be longer spans of time? Are they even actual periods of time at all?
You may protest: "The Bible says 'day,' so it's a day. The Bible says it, and I believe it!" This declaration is a good example of making the text say what you already think it should say. Where did you get the idea that the "days" of Genesis must be 24-hour periods of time? Not from the text of Genesis, but from the influence of our modern standards. We want literalty. We want scientific verifiability. We want details. Thus, you read Genesis "literally." At this point many of you will explain that the Hebrew word “yom” means “day” and it refers to a 24 hour period. Maybe it does. I’m not a Hebrew scholar. I understand, however, that a word in any language can be used literally or metaphorically. Even if you’re right about yom, you haven’t made an air-tight argument for your view.
You claim that those who interpret the "days" of Genesis as other than 24-hour periods of time are "not taking God at his word" and are "changing the Bible," yet the ones who force their own views on the text (and consequently force their views on the universe by trying to make the data appear to support their preconceived conclusion) are, for the most part, the young earth proponents.
Genesis 1 is not a scientific manual; it was not intended to be one in the first place. It is wrong to apply our modern standards to a book that is not based on such standards. A technical, detailed account of all the minute details of creation was obviously not the author's intent.
Genesis 1 most closely resembles Hebrew poetry. The author made use of common techniques of Hebrew poetry; furthermore, there is evidence to suggest the writer of Genesis, as well as other writers of the Bible, utilized a foundational schema. Foundational schemata are "cultural models which organize the diverse systems of knowledge and belief that comprise a single culture. From the actor's point of view foundational schema give the culture its feeling of sameness and continuity."  Dr. Gary Hall, professor of Old Testament at Lincoln Christian Seminary, has noted that there is a "6+1" pattern repeated throughout the Bible. The most obvious example is the creation account: 6 days of creation + 1 day of rest.  A foundational schema such as this "6+1" pattern is not used for the purpose of giving precise details - it is a literary and cultural tool used to organize and convey a message.
Considering the poetic genre of Genesis 1, along with the foundational schema of "6+1," a case can be made that the author fit the creation account into the "6+1" pattern, and, consequently, the "days" of Genesis aren't really days at all.
In the "evolution vs. creation" debate, creationists are losing. You are losing, because: (1) the evidence in support of evolution is overwhelming; (2) you have created a false dichotomy by arguing that evolution and creationism are the only two options, they are mutually exclusive, and if one of these options is wrong the other must be correct; and (3) you are playing a game you cannot win, for when you apply modern standards to a literary work that wasn't written according to modern standards, the work will naturally fail to pass the standards. To force the text into saying something it might not say at all (which is exactly what you do) is an act of desperation.
“Evidence is always subject to interpretation by fallible people who do not possess all information.” In light of both the evidence and your own admission of fallibility, can you continue to defend your position with the confidence and certainty which has become so characteristic of you?
I know you will say you can. To admit otherwise would be to suggest that you could be wrong. And certainly you can’t be wrong. “The Bible says it.”
1. Answers in Genesis: Statement of Faith
2. Topography of a Zambian Storyland by Gary Burlington - see p. 79 (This document is in pdf format.)
3. I am grateful to Dr. Gary Hall for responding to my email and providing me with this list of examples of the "6+1" schema:
The 6 + 1 archetype pattern in the Bible:
Gen 1 6 days of creation, a day of rest
Gen 30:20-21 Leah had 6 sons, then 1 daughter
Exod 16:26 Israel was to gather manna 6 days, but not on the 7th
Exod 20:8-11 6 days of work, rest 7th day
Exod 21:2 Hebrew slave work 6 years, goes free on the 7th
Exod 23:10 Grow crops 6 years, let land rest on the 7th
Exod 24:15-16 Moses on the mountain 6 days, God calls to him on the 7th
Exod 25-31 A 7-part literary structure to the instructions for building the tabernacle, 7 “the Lord spoke to Moses” phrases. The 7th section concerns observing the Sabbath (25:1; 30:11,17,22,34; 31:1,12)
Exod 25:31-40 Specific instructions given for the 6 side branches of the lampstand, implying that the 7th was different
Num 28:1-10 Offerings for 6 days are the same, are different on the 7th
Josh 6 Israel marched around Jericho once a day for 6 days, on the 7th day marched around 7 times and blew trumpets. The trumpets were blown on the first 6 trips, on the 7th they gave one long blast.
I Kings 6:38 7 years to build the temple
Job 5:19 6 calamities and 7
Prov 6:16-19 6 things even 7, and the 7th is a different order
Ezek 46:6 6 rams and a lamb to be offered
Gospel of John 7 signs, the first 6 are Jesus’ miracles, the 7th is his resurrection (2:11; 4:54; 6:2,14,26; 9:16; 12:18; 2:18-19 refer to his resurrection as a sign)
Jude 14 Enoch, the 7th from Adam was different
Rev 6:1 - 8:1 7 seals open, the last different from the first 6
Rev 8:2 - 11:19 7 trumpet blasts, the last is different