In reality for most young people who take science courses, the slippery slope of Bible interpretation about creation slides from doubt about a 6,000-year-old earth, to doubt about Josiah's long day, to doubt about Jesus walking on water, to doubt His miraculously feeding the 5,000 and the 4,000 to doubting Jesus' bodily resurrection.Perhaps such a path of doubt does occur. But if so, it has almost nothing to do with any logical link between an old Earth and denial of Resurrection. Rather, it has everything to do with poor hermeneutics, poor Bible teaching, and poor training in critical thinking.
Creation, walking on water, feeding 5,000, and rising from the dead are all miracles. The possibility or probability of miracles (and more particularly of the miracles recorded in Scripture) depends entirely upon whether we live in a world accurately described by Christian theism or one more accurately described by scientific naturalism ('the universe is the whole show; no god exists'). For the purposes of this argument, I'm talking about and to only those people who acknowledge God and the accuracy of the Bible's accounts of miracles.
Now, one possible problem--for those many young people taking science courses--is that they have never been taught to recognize worldview differences. That is, they go into science class expecting their professor to teach them the truth, the whole truth, and nothing but the truth without any worldview bias when, in fact, that professor begins by adopting a naturalistic worldview and discounting the possibility of a Creator. Worse, if the Christian young person has wrongly been taught that the Bible somewhere claims that the universe is only 6,000 years old, then the naive young person's doom is sealed because the professor has overwhelming evidence from virtually every scientific discipline to demonstrate the absurdity of that view.
Let me spell it out as simply as possible...
Scripture claims that Jesus walked on water.
Scripture claims that Jesus fed 5,000 people by multiplying a small number of loaves and fishes.
Scripture claims that Jesus rose bodily from the dead.
Scripture claims that God (through Jesus) created the entire universe and everything in it.
Scripture nowhere claims that the Earth and universe were created only thousands of years ago. This is merely one interpretation of how to understand Genesis 1 and the other relevant passages. By my count, there are at least 13 different interpretations of Genesis 1 that are held or that have been held by Christians committed to the inerrancy and reliability of the Bible. Only two of these 13 interpretations lead to the view that the Earth is only thousands of years old. To put it the other way around, the vast majority of the interpretive positions about Genesis 1 held by committed Christians now and throughout church history either allow for or demand the vast age of the universe and Earth that the creation itself indicates.
The young-earth interpretation does not--as its very vocal modern proponents claim--involve a straightforward reading of the text. It involves at least 5 assumptions, each of which is either quite controversial among Hebrew linguists and Bible scholars or even demonstrably false.
What's more, while Christians throughout the ages have wrestled with the proper understanding of the creation accounts, belief in a young Earth and universe simply has never been a part of historical Christian belief. It is not found in any creeds, and has never (except by those in the last 60 years who have spent their careers promoting this young-earth interpretation) been seen as necessary to salvation or to the doctrine of Biblical inerrancy.
There is a very clear logical link between belief in the miracle of Resurrection and belief in the miracle of creation. And belief in the latter is more reasonable today than it ever has been,* as the latest evidence from nearly every scientific discipline overwhelmingly supports the Biblical understanding of the universe in which we live. Unfortunately (for some), none of that evidence supports the view made popular only last century, that the Earth and universe are only thousands of years old.
If our young people begin to doubt the truth of historic Christianity when faced with evidence from science, then the main problem is that they have not been taught to think well, not been taught to interpret Scripture well, or--worst of all--been taught a modern mischaracterization of historical Christianity and what the Bible teaches (and doesn't teach) about creation.
By the way, it was Joshua--not Josiah--for whom "the sun stood still."
*That is, for the person who hasn't already had a personal, life-transforming encounter with the living, risen Lord and Creator.