When my close friend in secondary school told me about her first and current impressions of me

In secondary 3, I took the same elective subject as a close friend of mine. We took art together with my sister and another friend of ours and sat together in class. One day while walking from our previous lesson to the art room, I confidently proclaimed something that was entirely wrong again, with my group shooting me down with evidence. While contemplating life as I realised my shortcomings, the close friend in question said that she did not expect me to lack that much intelligence. She explained that in our initial encounter, I looked like a mature and quiet individual, but after a long time of hanging out together, she said that she realised how stupid I was. I was surprised, but we laughed as it was in good fun.