The paper presents the development and initial validation of the Senescence character framework, a simulation tool that can be used for rigging muscle deformer-based humanoid characters, with support for age. The senescence framework allows the user to rig any bipedal 3D character and manipulate skeleton and muscle parameters in order to render the age of the character realistically. The framework was developed using Python, Maya Embedded Language and PyQt. A study with 100 subjects was conducted to determine whether participants were able to perceive the age of the characters simulated with the Senescence framework. Findings show that while subjects were able to perceive age differences, they were not able to identify the age of the simulated characters with high level of accuracy. Results also show that subjects with animation expertise were able to identify the age of the characters more accurately than subjects without animation experience.