How can we explain rising levels of pre-marital sex in post-war Britain? Focussing 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 girls related to those around them and the decisions 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 everyday sexual experience but we uncover new processes of socio-sexual change.