PMP Practice: Estimate project tasks (milestones, dependencies, story points)

Cedar Petersen is leading a product development project at Silver Badger Consulting to create a new mobile app for personalized fitness coaching. The executive sponsor initially requested a detailed 18-month Gantt chart with milestone dates for executive review. However, after the first stakeholder workshop, it becomes clear that user preferences and competitive features are changing rapidly in the market. The marketing team reports that three competitors launched similar features in the past two months, and customer feedback from a prototype session revealed unexpected preferences that differ significantly from initial assumptions. The development team has strong technical skills but limited experience with the current AI frameworks required. The sponsor now wants to see working features every month to make funding decisions and adjust market positioning. What approach should Cedar use to manage the schedule going forward?