Hello,
Age data is an internally-managed variable, so there’s no way to directly alter/manipulate it from outside of low-level tracker.
If you want to inject a custom object, I would recommend to add a custom object as a part of NvTracker input, which is NvDsMetaList. To make the added custom object to be alive inside the tracker, you would need to feed the custom object input for a few frames like longer than probationAge