In this paper, we develop a novel model of opinion dynamics that takes into account the variability of self-confidence. This agentbased model aims at combining both opinion and self-confidence, two notions often assimilated in many modeling works, although well distinct in practice. We analyze our model under two types of opinion space, namely a standard interval and a circular structure under which the system presents some intriguing specificity. We give some insights concerning the global equilibria of the co-evolving dynamics, and also highlight some salient features of the global system's trajectory. Finally, we conduct several numerical simulations to support the analytical results.