Abstract: Absolute stellar ages are some of the most sought after astrophysical quantities, especially for identifiably young systems that provide constraints on time-dependent features of planet formation and evolution. However, accurate ages for young stars remain elusive due to a necessary reliance on stellar evolution models, which are beset with problems for ages younger than 100 million years. I will highlight the most pressing issues facing young stellar models and efforts to explain these problems by considering non-standard physics, such as accretion and magnetic fields. I will demonstrate that including non-standard physics in young stellar models improves their agreement with observations, but that fundamental uncertainties limit our understanding about which physical processes are required to accurately model young stars. I will conclude with a discussion of these uncertainties and new efforts to relieve them.