The Bible's 1st mention of a camel was when Abraham's future daughter-in-law arrived to marry his son Isaac:
Ge 24:64 Rebekah also looked up and saw Isaac. She got down from her camel
Actually, Gen 12:16 is first mention of a camel (camels) in the Bible.
Nobody really knows when the book of Job was written but many date it as far back as 2000-1800 BC. Genesis was written in about 1450-1410. If that is correct, then Job would be by far the oldest book and in Job 1:17, we are told that he owned 3,000 head of camels.