Based on the paragraph, the underlying emotion that is described is Lara's nervousness. There are many phrases that pinpointed to this emotion, and these are as follows: hesitated, sweaty, downcast eyes, shuffled, timidly. These speak of a person that is uncertain or afraid.
She cannot be excited because of the word "timidly" which is the exact opposite of excitement.
She cannot be disappointed because it seems that it is just the first time for her to be in the class thus she does not have any expectations yet.
Compassion is simply out of context in this paragraph.
