The use of LLMs (Large Language Models) as "thinking partners", conversational partners actively partaking in user's reasoning, is on the rise. As young adults become the demographic that engages with LLMs the most, concerns over whether different AI "thinking partner" styles can help or hinder responsible opinion formation become more prevalent. This study investigates how three "thinking partner" styles, Steelman, Socratic, and Neutral, affect opinion change, epistemic trust, and epistemic autonomy in simulated young adult participants. A between subjects study was conducted, using simulated personas as participants. Each persona engages with a "thinking partner" condition for a five exchange session on the topic of individual versus systemic responsibility for climate action. Opinion change differed significantly across conditions, with the Steelman producing a shift away from individual climate action, while the Socratic and Neutral produced comparable positive shifts towards agreement. No significant change was noted for epistemic trust and autonomy, both of which were rated consistently high regardless of the condition. These findings suggest that an adversarial AI may provoke resistance rather than persuasion, while trust and sense of autonomy is preserved across interaction styles. This study serves as a preliminary methodological pilot, future work should replicate the experiment with human participants. ... Read more