The goal of this clinical trial is to reduce diabetes distress in emerging adults (18-35 years) with type 1 diabetes and moderate-to-severe diabetes distress. The expectation is that a group-based psychological intervention (ACTnow) will not only reduce diabetes distress but also improve psychological well-being and glycemic outcomes. The intervention involves a multidisciplinary team, including nurses, psychologists, and physicians, and is designed in a format that can easily be integrated into future standard care. The main research questions are: * Does a group-based psychological intervention reduce diabetes distress? * Does a group-based psychological intervention improve psychological well-being and glycemic outcomes? Researchers will compare the group-based psychological intervention (arm 1) with a waitlist control group, which will receive the intervention after three months (arm 2). Participants will first attend a virtual screening interview with a psychologist or nurse to identify if they are eligible to participate in the study. After randomization, the intervention group receives six bi-weekly sessions, each lasting two hours, led by a psychologist and nurse. Each session includes a mindfulness exercise, a review of the previous session, a new topic, individual homework assignments, and a conclusion.