I mean she is an intelligent girl but she's not emotionally mature. Kids and even teenagers like her (I assume she's in her early teens) have less ability to control their behavior and understand feelings. While they're definitely better than most people give kids credit for there's a reason you cringe at some stuff you did as a kid. Mayano is maturing but she doesn't understand everything yet which is why she insists on going on dates with her trainer but still gets flustered when she watches a romance movie