I hope the Bible will remain important to you, and that you will never lose your confidence in it, for it is still God's Word—regardless of what some people suggest. Jesus put it succinctly: "Your word is truth" (John 17:17).
I too am surprised by what your professor said, because very few scholars who have seriously studied the Old Testament would agree with him. A few generations ago, some might have made such a sweeping claim—but not today. One reason is because of the vast number of discoveries that archaeologists have made during the last century—discoveries that repeatedly confirm the historical accuracy of the Bible. Your local Christian bookstore can suggest further reading for you if you are interested.
Since the dawn of history, some have denied God and tried to cast doubt on His Word. In fact, the very first question in the Bible came from the lips of Satan, and his purpose was to convince Adam and Eve that God's Word could not be trusted: "Did God really say ... ?" (Genesis 3:1).
Don't be misled by these claims, but put your faith firmly in Christ, the divine Son of God who walked on this earth and gave His life for your salvation. Then make the Bible part of your life every day, for "Your word is a lamp to my feet and a light for my path" (Psalm 119:105).