Continuity mistake: After Casey has turned down Harvard and is skating on the pond, she falls many times. When she falls for the fourth and final time, her hat falls off. In an overhead shot, the camera even shows it laying on the ground above her head. When she gets back up upon seeing Teddy with the zamboni, her hat has disappeared.
Continuity mistake: When Casey is skating on the pond after she leaves Harvard, she falls multiple times. The second time she falls, she lifts her right leg causing her foot to come into frame. On her feet you can clearly see that she's wearing black and green snow boots, even though seconds before that she was wearing white figure skates.