21st century preparedness is a prevalent topic in the field of education. The Common Core State Standards were developed to promote continuity for all students. Research indicates that student preparedness for college and the workforce is lacking. In order to bridge the gap, students must become intellectually autonomous. In addition to content knowledge, students must possess the ability to be creative, think critically, and collaborate to be successful beyond high school. The school site of this study developed a STEM cohort through grant funding. The four teachers interviewed shared stories of their journeys as they began transforming their classrooms to become more experiential in nature by implementing project-based learning. The impetus for the transformation was through perpetual professional development. The purpose of this qualitative study in the narrative tradition was to explore the lived experiences of the STEM cohort to better understand their transformation. The research was framed by the following questions: (1) How do teachers, as adult learners, describe their transition from traditional classroom environments to more experiential? and (2) How have teachers, as adult learners, been prepared to teach in a PBL environment? The conclusions were as follows: the degree to which teachers were prepared to implement and sustain the PBL initiative relied heavily on thoughtfully executed professional development that considered the adult learner. Through the categorization of values, attitudes and beliefs, teachers expressed the need for relevance, collaboration, and a shared vision with innovative leaders to maximize the efficacy of professional development. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]