They taught you fairy tales as fact.
Perhaps, but who taught you? How do you really know for 100% certainly that what you have been taught is true and not some concoction? I would really like to know how it is that you came to believe that the earth is flat. What is it that makes you believe that what you were taught is really true?
I believe that the government lies all of the time and that through the years the schools have taught a lot of nonsense but not everything is nonsense or for that matter a lie.
I don't have a 100% certainty that the earth is round because I have never been into space. My belief is based, whether true or false, on the evidence I have seen. I have noticed a curve to the earth when flying though I would not say that this is conclusive evidence to support my belief.
Really, how do we know anything that happened in the past is true? Maybe the whole thing is a lie. That really wouldn't surprise me. The only thing that I know for 100% certainty is the truth contained in the Word of God, that Jesus died for my sins, that the Holy Spirit lives inside of me and guides me and that I will spend eternity in the presence of God.
At that time the question of whether the earth is flat or round will be put to rest as it would be irrelevant as there will be a new heaven and a new earth.
Probably round.