When you get nostalgia
For previous episodes, books, volumes, or songs
When you understand the world better
By comparing it to a million fictional ones
When you obsessively hit the reset button on YouTube
Waiting for the next episode or song to come out
When you have tons of fictional or celebrity crushes
But don't like anyone in your school
When you understand the characters
Better than the people around you

That's when you know you're a fangirl