Characterization of Clara

In the following passage from a novel, a character named Clara is introduced. The author describes Clara's reaction to unexpected news:

"Clara's heart raced as the words sunk in, a mixture of disbelief and frustration flashing across her face. She clenched her fists, wishing for a moment she could rewind time and prevent the conversation from happening. Her mind raced with possibilities, each one more daunting than the last, and despite her best efforts to maintain her composure, a lone tear escaped down her cheek."

Based on this passage, how is Clara characterized?