AITA for thinking that cheating on my exam is my business?

Throwaway account because I can.

A little bit of background. I was recently enrolled in a history class that was necessary to achieve my associates degree. I have never had any interest in history and as a result have really struggled with it therefore I don't really see a problem with doing everything in my power to get through the class and onto something I'm actually interested in. Anyways here's the scenario.

I recently was taking a history exam and a peer called me out for looking at my phone while the professor was out of the room. My peer said "That's enough. People study too hard for this shit" too which I replied "that's why I'm looking at my study guide" and quickly put away my phone. Given I was looking at my study guide on my phone which is against the rules am I the asshole for thinking that since I'm paying for the class and it's my education it should really be none of that students business? The professor has never graded on a curve so I can't see it affecting my peers in anyway whatsoever. Let me know. I think it's up for debate.