Persistent gender gaps in self-promotion contribute to unequal labor market outcomes. In this study, we investigate how AI-assisted writing tools shape self-promotion, and, as a secondary outcome, confidence and how these effects interact with gender. For this purpose, we conducted an online experiment in China in which participants wrote self-promotion texts, provided a numerical self-promotion score and stated their confidence about how they will perform in an upcoming math and logic test. We find suggestive evidence that AI assistance reduces numerical self-evaluations. Neither gender nor the interaction between gender and AI assistance is significantly related to self-promotion or confidence. We conduct a text analysis to investigate the mechanisms behind these results.