Background: Breast cancer survivors are at risk for developing cardiovascular disease due to cardiotoxic cancer treatment. Research on young breast cancer survivors (diagnosed < 45 years old) are limited. Methods: Young breast cancer survivors diagnosed between age 30 and 44, stage I–III, and treated at the University of Alabama at Birmingham Hospital between 2012 and 2015 were included. Cardiovascular disease risk was estimated using excess heart age (calculated using age, systolic blood pressure, blood pressure medication, diabetes, smoking, body mass index) and examined at two time points: diagnosis and 2-year follow-up. Statistical analyses included within-group mean comparison tests and linear regression to examine predictors of excess heart age. Results: A total of 152 young breast cancer survivors were included; 95 received anthracyclines and/or trastuzumab, and 57 did not. Overall excess heart age was 4.2 at diagnosis and 5.4 years at 2-year follow-up (p = 0.08). Change in excess heart age from diagnosis to 2-year follow-up among those receiving or not receiving anthracyclines and/or trastuzumab was 4.3–4.4 years, p = 0.93; and 4.0–7.1 years, p < 0.01; respectively. Factors that predicted excess heart age included endocrine therapy (p = 0.049) and change from premenopausal to postmenopausal status (p = 0.048). Conclusions: Anthracyclines and trastuzumab were not predictors of excess heart age. Subclinical changes undetected by heart age may still occur. Future research is needed to evaluate heart age over longer follow-up and to develop a modified heart age tool, that incorporates treatment risk, that facilitates identification of high-risk cancer patients for early intervention in cardiac risk prevention.