Purpose offers several important benefits to youth. Thus, it is necessary to understand "how" a sense of purpose develops in supportive contexts and "what" psychological resources can help. From 2021 to 2022, this study investigated purpose change among 321 youth (M[subscript age] = 16.4 years; 71% female; 25.9% Black, 33.3% Asian, 15.6% Hispanic/Latinx, 13.4% White, 9.7% multiracial) participating in "GripTape," a [approximately]10-week self-driven learning program. Many youth started with high initial purpose that increased throughout enrollment ("Strengthening"), whereas others began with slightly lower purpose that remained stable ("Maintaining"). For each unit increase in baseline agency, youth were 1.6x more likely to be classified as "Strengthening." As such, agency may be a resource that helps youth capitalize on certain types of environments.