Scripture supporting a young Earth
"And God called the light Day, and the darkness he called Night. And the evening and the morning were the first day".
Genesis 1:5
In the fifth verse in all of the Bible, not only does God name the periods of day and night, but we can clearly read the second half of the verse as meaning that the period of time for each day of Creation is a literal 24 hour period day as we experience now as well. The verse states "the evening and the morning were the first day". Evening and morning frame literal days which are 24 hour periods, the morning starts a new day and the evening ends it. If this were not enough to convince a reader we also have the last part of the verse. It states clearly that this day is "the first day". The grammar in this part of the verse helps us understand that this was the first day in our planets history. How many the first day's have there been in our history? One. There can only be one first day. Genesis 1:5 is a crucial verse in scripture in helping us understand our history and the timeline of it. It also helps establish the framework of our days and weeks by seeing that they have always been 7 day weeks based around 24 hour long days.
Many "skeptics" will point out that this defense is based on modern translations and would be useless in defending the original texts. However when Moses originally wrote Genesis in Hebrew he carefully used the term yôm, which is the Hebrew word used to describe a 24 hour long day. Nowhere in scripture is the yôm ever used to denote any other length of time. In addition to this, he also pairs the term yôm with numbered days such as "the first day", "second day", etc. And even framed them with "evening" and "morning". Through this first establishment of the definition of the term yôm we can clearly know that when the word was used it is meant to refer to a 24 hour period of time and none other. Such specific langauge rules out any alternative interpretation of the timeframe between the days of creation.
"This is the book of the generations of Adam. In the day that God created man, in the likeness of God made he him"
Genesis 5:1
In Genesis 5 we find the geneology of many people listed in the Bible for several thousand years of lineage. By tracing human lineage back we find that we can not go back more than roughly 6,000 years into the past. If there were humans alive on Earth longer than this there should be evidence for it, but as of yet no one has ever discovered any reliable sources to date mankind back further than around 6,000 B.C. Why would people wait until only around 6,000 years ago to start recording history?
In addition to this the genealogoies provided in the book of Genesis gives us numerous reliable eye witness accounts from Moses who wrote Gensis (as well as several other books), but also from the individuals listed in the genealogies, meaning that each person listed was known firsthand by someone who detailed their age and family tree. Due to the longer lifespans of people during this time, it is possible that this information could have been passed orally down beginning with Adam himself.
One more property of the timeline established by the genealogies is the fact that the term begat is only ever used in the Old Testament to mean one generation, ie. father having a son. This eliminates the possibility of gaps in the genealogies.
In short, the genalogical records in Genesis are an extensive record of our history as humans starting at the beginning with the first man and woman. It is given to us to know our origins and our place and purpose as God's children, made with love and care.
"But from the beginning of the creation God made them male and female."
Mark 10:6
In one of His many sermons, Christ references, among many things, the creation account that is layed out in Genesis. He mentions that since the beginning humans have been made male and female. Aside from the obvious connotations on gender equality and marriage, this statement by Christ Himself shows us that He considered the creation account to be a literal event.
This statement ties into the creation account which states that God made them male and female at the beginning during the creation event. Christ is qouting Genesis 1 and 2, meaning that the male and female He is referring to are Adam and Eve, the first humans.
This is not simply referencing the first humans, but all of creation. the phrase "from the beginning of creation" is also used in Mark 13:19 and 2 Peter 3:4. In 2 Peter 3:4, Peter is referencing the past and future of the entirety of the heavens and the Earth with this very phrase, meaning the phrase applies to the beginning of creation of all things in our Universe and world, not simply the first humans as some Old Earth believers would assert.
"For those days wil be a timeof tribulation such as has not occurred since the beginning of the creation which God created until now, and never will. Unless the Lord had shortened those days, no life would have been saved; but for the sake of the elect, whom He chose, He shortened the days."
Mark 13:19-20
Luke 11:50-51