How can we explain rising levels of pre-marital sex in post-war Britain? Focusing on the experiences of young women growing up in Britain between 1950 and 1980, this article argues that changes in sexual practice were brought about by shifts in the social value of sexual knowledge and experience. While the figure of the ‘nice girl’ was still central to understandings of respectable femininity, across this period social status and reputation became linked to demonstrations of attractiveness and sexual knowing. For girls of the post-war generation, discussions of sex were central to how they related to those around them, and the decisions that teenagers made about their own sexual practice were informed by their perceptions of what their friends and peers would think of them. The article argues that, by considering the history of sexuality at a ‘local’ scale between the macro-level of culture and the micro-level of individual sexual selfhood, we not only gain an important new perspective on the everyday sexual experience but also uncover new processes of socio-sexual change.