As mobile devices become central to modern life, elderly users often struggle with their complexity, leading to digital divide. This paper explores how the integration of Human-Computer Interaction (HCI) principles and Natural Language Processing (NLP) techniques can enhance the way elderly users learn to use smartphones. To demonstrate this approach, we present AgeMate, a prototype mobile agent designed to support seniors in acquiring smartphone skills more intuitively and effectively. Specifically, we investigate how personalizedfeedback generated by large language models (LLMs), appropriate granularity in instructional content, and mechanisms for preventing and correcting user errors can contribute to more adaptive and user-friendly learning experiences for elderly users. Rather than focusing solely on system performance, our study emphasizes the instructional value of NLP-enhanced interaction: enabling step-by-step, conversational teaching tailored to users’ real-time context. By analyzing usage patterns and interaction challenges, we propose design strategies that bridge the gap between accessibility and intelligent guidance to better support elderly users in digital environments.