Purposes: Women with diabetes (WD) are more severely impacted by the consequence of suboptimal diabetes control. This study aims to examine the impact of demographic and disease characteristics, baseline self-stigma, role strain, diabetes distress on Hemoglobin A1C (A1C) levels, quality of life (D-QoL) and 6-month A1C levels in younger WD. Methods: This study was a 6-month prospective study. In total, 193 WD aged 20–64 years were selected by convenience sampling from three outpatient clinics in Taiwan. Demographic and disease characteristics, self-stigma, role strain, diabetes distress, A1C levels, and D-QoL were collected at baseline. A1C levels were further collected 6 months later. Structural equation modeling was conducted to test the hypothesized model. Results: The final model supported that higher baseline D-QoL directly associated with lower concurrent A1C levels and indirectly associated with lower 6-month A1C levels through baseline A1C levels. Higher baseline self-stigma, role strain, and diabetes distress directly associated with lower baseline D-QoL, and indirectly associated with higher 6-month A1C levels through D-QoL. Conclusion: Improving self-stigma, role strain, and diabetes distress should be considered as promising strategies to improve D-QoL in young WD. D-QoL plays a mediation role between baseline self-stigma, role strain, diabetes distress and subsequent glycemic control in younger WD. Enhancing baseline D-QoL is fundamental to improve subsequent glycemic control.