Although Internet use is increasing, older adults have still difficulties to use computers. This study presents three assistant agent models, a local model, mobile model, and pocket model, to assist older adults in using the Internet easily. This study analyzes scenarios for the three models, and compares their total system delay time when used by older adults. The goal is to identify the best model of an assistant agent to decrease difficulty when accessing information on the Internet. In terms of performance error, the local model is more suitable than the other models for use by older adults. However, in terms of mobility, the mobile and pocket models are more suitable than the local model. Additionally, this study presents three mathematical models of agents and assesses their respective advantages and disadvantages.