He never thought the one who first falling to the other is Xavier and not him. He believes that time he was the first one who falls for him in their first meet. That time he doesn't know the one who save him from the bullying is Xavier, so he presumes the first time they meet is when Xavier suddenly enters the Art Building where he was in his task to draw a proposal for the mural in the entrance on the sketchbook. That sketchbook will send to his Art teacher to make them choose which drawing they want and agree before he could start his mural painting project at the entrance of this building.
Now he wonders, why Xavier never mention the first time they meet is when he was fainted not when he accidentally enters the class where he was drawing. Not accidentally but actually already planning to see him that was just his excuse to make sure he didn't feel uncomfortable maybe.