Increasing student retention and persistence -- in particular classes or in their major area of study -- is a challenge for universities. Students' academic and social integration into an institution seems to be vital for student retention, yet, research on the effect of interpersonal interactions is rare. Social network analysis is an approach that can be used to identify patterns of interaction that contribute to integration into the university. We analyze how students position within a social network in a Modeling Instruction (MI) course that strongly emphasizes interactive learning impacts their persistence in taking a subsequent MI course. We find that students with higher centrality at the end of the first semester of MI are more likely to enroll in a second semester of MI. While the correlation with increased persistence is an ongoing study, these findings suggest that student social integration influences persistence.