Post-secondary education is meant to build the cognitive and professional growth of the students studying all subjects. Yet, little is known about the development of how students think of themselves as members of the field, nor how they develop from a young novice to a person eligible for employment. A lens of self-authorship was used to compliment and interpret data collected regarding how students think of themselves as member of the STEM community (STEM Identity) and how they perceive their achievement STEM Identity. There was a significant link between student-mentor experiences and a higher professional identity and more progress along the continuum of Self-authorship. Additionally, in interviews much qualitative data was collected to indicate that the role of the mentor was significant in the development of these young professionals, and in-person mentor experience were preferred (in the time of the COVID-19 pandemic, virtual meetings were a norm). Implications for this research and suggestion for future investigations are given. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]