The current study aims to evaluate and compare the subjective quality of an AI-based training system developed for conducting child interviews, focusing on the distinction between immersive 3D (using virtual reality) and 2D desktop environments. To this end, a structured user study was conducted, involving 36 participants who were exposed to these two distinct environments. The study evaluated various aspects of user experience, namely presence, usability, visual fidelity, emotion, responsiveness, appropriateness, and training effectiveness. The findings reveal significant differences in user experience between the 2D and 3D environments. Notably, the 3D environment enhanced presence, visual fidelity, training effectiveness, and empathy. In contrast, the 2D environment was favored for usability. The study highlights the potential of immersive VR while also pointing out the need to improve the system response and emotional expressiveness of the avatars.