A lack of diversity permeates the science, technology, engineering, and mathematics (STEM) field. Under-representation within STEM fields can stifle innovation and progressive approaches to the future of STEM. Traditional STEM pathways focus on identifying participants who show academic promise in schools. One segment of young people, youth who have been "pushed out" of high schools, have often been excluded from STEM pathways. Alternative education programs have the potential to support youth who have been pushed out, to re-engage in STEM. The purpose of this study was to understand what factors contributed to the STEM aspirations of students at Xinaxtli Charter School (XCS), an alternative education program for youth who have been "pushed out" in South California. This quantitative study utilized Structural Equation Modeling to analyze a conceptual model for STEM aspirations at XCS. Specifically, this study looked at how each of the following areas -- student perception of their science teacher, critical science education, student sense of agency to create knowledge in science class, student engagement in science class, and the relevance of science to the student -- impacted student STEM aspirations. The best predictors of student STEM aspirations came from the following factors: (a) Relevance of science to students, (b) student sense of agency to create knowledge, (c) and critical science education. Findings from this study provide a framework for educators of STEM classrooms to re-engage youth who have previously "pushed out" of their traditional secondary schools.