Academic achievement, often measured by GPA, has been extensively studied in the literature of science, technology, engineering, and mathematics (STEM) education, including its impact on student persistence and success in college (Rask, 2010). However, most research has only looked at students' performance at a single point in time, such as their first-year GPA, and has not explored how their academic performance changes over time. As a result, there is a gap in our understanding of the longitudinal aspects of students' intellectual journeys through college. This study aimed to fill this gap by adding a nuanced understanding of the academic performance change patterns of a group of initially STEM-intending college students at State University and was guided by two research questions: (1) what are the change patterns in those students' academic performance across different semesters?; and (2) how are these patterns related to their background and college experiences?