RE: INTRODUCTION: "I think earth might be flat. Why do we trust NASA so much...?"
I would encourage you to make a lengthy investigation of this subject before judging so quickly.
It is unknown to most people that tests have already been conducted which prove that the geocentric model of our Universe is in fact far more likely to be accurate than the heliocentric model we have been conditioned to believe as truth.
The idea that humans are positioned at the centre of the Universe is a very dangerous one for those who seek to control us. They would much rather we believe that we are nothing special and the product of pure chance... floating somewhere on the outer rim of the Milky Way, with the sun as the centre.
You will find upon investigation that there are many things about the globe earth idea which simply don't add up.
I cannot say for sure what we are living on, which is why I refer to it as a playground these days.
What I can say for sure is that there is a well established control system which does not seek to tell us TRUTH. Only to continue their grip of control. And there are many ways in which this is achieved.
Question everything my friend. The rabbit hole goes deep.