Resumen: [EN] This study delves into the transition from secondary to tertiary mathematics education, a pivotal moment impacting cognitive, social, and cultural domains. Through personal journal analysis and using the theoretical framework of the “rite of passage”, it investigates the experiences of first-year Architecture students at Politecnico di Milano. Text analysis confirms five prevalent themes described in the literature: instrumental/relational mathematics, structural differences between university and high school, adjustment process of self-regulation strategies, the development of a new identity as mathematicians, and social integration with peers. This research contributes to ongoing efforts in mathematics education, aiming to improve the overall transition experience and academic success of tertiary education students. In particular, the study sheds light on the complexities involved and shows as the journal practice can provide a deeper understanding of student challenges, perceptions, and adjustment processes.