We have followed a group of students in the potential pipeline for science through their last years of upper secondary school and in the context of a university mentorship program. The student group is defined by their choice of Mathematics at A-level which is mandatory for admission to tertiary STEM education in Denmark. Rich data (repeated interviews, questionnaires (pre-and post-) and observations) from 14 target students have been collected. Using Late Modern identity theory as a lens, we have analysed students' identity narratives in order to establish their trajectories in relation to university in general, and towards science studies and science careers in particular. We find that the diversity of students' educational identity narratives can be characterized and their trajectories understood in terms of a Four Factor Framework comprising: general "identity process orientations" ("reflecting," "committing," "exploring"), "personal values," "subject self-concepts and subject interests." In various ways these constructs interact and set the range and direction of the students' searches for future education and careers. Our longitudinal study suggests that they have enough permanence to enable us to hypothesize more or less secured paths of individual students to tertiary science (or other areas of academia).