Welcome!
Well, your teacher is right & wrong. What they unfortunately attempted to do is address a complex issue in a simplified way and without sufficient time to go deep enough into it.
You have to really start studying your bible with good solid Catholic teaching & the Catechism too.
The Church has always taught that scripture has several “senses” including the literal. The first 10 chapters of Genesis can be interpreted as a “story” as your teacher called it only in the sense of the days of creation not necessarily being literal 24 hours, and that the creation story does tell us about our origins, sin, and man’s relationship to God. There are elements of the story that go beyond the literal, but you cannot toss out the literal.
Are we free to interpret that Adam and Eve did not exist? NO. While it is a “story” i’ts MORE than “just” as story. Does that make sense at all?
Maybe studying the bible in more detail would help. Specifically getting some books on
how to study the bible (from a solid Catholic source like Ignatius Press).
Visit
www.salvationhistory.com for some good bible study tools.