When you create an auto-labeling policy for sensitivity labels and start it in simulation mode using the default settings, Microsoft Purview will automatically turn on the policy after 14 days if you make no changes during simulation. A policy created on February 1 would therefore be turned on on February 15.
References used:
Microsoft Purview Data Access Governance custom assessments item limits.
Exchange Online Managed Folder Assistant and Start-ManagedFolderAssistant.
Auto-labeling simulation mode behavior and automatic enable timeline.