I'm writing a book and i need a bit of help! Pleeeeassse help.

I am writing a book and i have a basic concept but i was talking to my mom and she said it sounds like to much..... basically its about girl who becomes best friends with another girl and then she tells the whole her secrets. Then they get stuck going to this school camp together that basically involves them to get into arguements. Then i wanted a twist so i was thinking of a stalker that ends up trying to hurt the girls. I know i can make it all work but...