The exponentially growing amount of digital information and data analysis increase the ability to perceive the holistic situation of people. This paper applies the digital twin paradigm to strengthen a person's ability to utilize information about themselves by creating a digital representation of their situation to support their well-being. More specifically, we propose a blueprint to empower individuals by improving their self-determination regarding their personal data. The blueprint will help service and data providers, both public and private, to develop a common understanding of the role and possibilities of a citizen's controlled personal digital twin of themselves -a Citizen Digital Twin (CDT) -for creating people-centric solutions. The blueprint also provides a rational framework for service development based on Citizen Digital Twins and serves as a basis for strategic guidance of service development. We demonstrate this with a case study of confirmation class students.