I feel Italia Ricci is not convincing

I watched Chasing Life (2014) and Italia Ricci was one of the parts I kept noticing. The role needs more detail, but the performance stays on the surface. I do not hate it, but it did not pull me into the story. Many moments pass very fast, and I do not remember much after them. Some emotions are too simple, and I cannot believe the character enough. This is only my personal view, but the performance changed how I enjoyed the film.