a fan
A fan is someone who thinks they know you better than you know yourself. They talk about you like you’re their best friend, even when you’re not.
My teacher is a fan of me. She says I’m the best student, even though I failed the last test.
My cousin is a fan of my dad. He talks about him like he’s a rock star.
My mom is a fan of my little brother. She says he’s perfect even though he eats my food.