Very interesting plot, but the entire story seems very rushed. To get people into really knowing the character you need to provide a background, emotion, feelings. I would have started with her playing withh hr sister or whoever she was playing with, and grumbling when the ball was hit into the bushes. Put in some banter, some background into her emotions and such.
If you notice when you read one of your favorite books, you always are in tune with the main character, with their, hopes, dreams, fears. When they're surprised, so are you, when they’re scared, your usually suspenseful of the reasons why.
Your writing is good, but the mood is very rushed. I don't feel that much time has pa.ssed, or really can tell she is so forlorn she wants to just curl up in a ball and cry. There isn't too much suspense when she spots the people, no weird feeling of their conversation, or terror when he rushes at her.
It takes longer writing but that is how you really suck a person into reading your stories. You have to make them love your character before they can be horrified that they're necks are being torn open by a vampire!
I’m not being mean, just trying to help you improve :)