She considers Eddie a father, and she wants his approval for everything she does, where this is seen from the beginning of the play, where she is desperate for him to approve her job and new skirt. Her character, however, develops from the middle to the end of the play, where she becomes stronger and more fierce when making her own decisions, such as marrying Rodolpho, even though this may mean she loses Eddie.
Later in the play we see her becoming too familiar with Eddie, as though not realizing how grown she is and how she must be careful on how she presents herself towards Eddie (as in not seeing him in her slip).
Catherine, however, remains loyal to Eddie, when telling Beatrice that she knows her marriage to Rodolpho would be wrong if Eddie didn't approve of it, however she is ready to take sides when Eddie spars with Rodolpho (end of Act I), she helps her lover. This may foreshadow how she will choose to marry Rodolpho in the end of Act II. She becomes more withdrawn as she does not know what to do with the two men she loves. "I mean I know him and now I'm supposed to turn around and make a stranger out of him?"
Despite her independence and maturity, she still blames herself for Eddie's death, as she says "Eddie, I never meant to do nothing bad to you."