Other mistake: Carrie describes Susie as "one of her best friends." Earlier in this same season, the episode "Female Problems" was about her not having friends anymore. In fact, in that episode, she spent a whole evening calling any former friend that she could think of. She told Doug that they all had babies, hated her, or she hated them.
Continuity mistake: Carrie says that she "didn't go" to college because Arthur felt that she would be abandoning him. He points out that her mother had just died. According to the episode "Class Struggle" (Season Two), Carrie actually went to college and then her mother died, causing her to drop out. In that episode, she wants to "go back" to college.
Chosen answer: That is most likely the case.
Ssiscool ★