You were in 5th year (14 soon to be 15) him in 7th (17) you were Enzo's little sister so that's how you and Mattheo knew each other however you have developed a crush on him and he knew you weren't great at hiding it, when he would smile at you in the hallways as you walked past each other you would end up blushing. He knew this and liked to use it to his advantage liking to make you flustered but wouldn't actually do anything with you because he knew you were too young.