At the beginning of the movie, it shows Ashley getting ready for school. It shows her putting on two necklaces. But when she gets to school she only has one thick one on.
Now, when Ashley Grant is getting ready for school in the morning, she does put on two necklaces, one brown and one blue. Then it switches to a scene of her spraying perfume on her neck, and you can clearly see that the two necklaces are pushed together. When she arrives at school, and she hands the book back to the boy who fell off of his skate board, you can see that she is still wearing the brown and blue necklaces. Pause it and look for yourself!