Kirby continued her goalscoring form into the 2015 WSL2 season, taking 11 goals in five league appearances for Reading, including all four goals in a 4–2 away win against Yeovil Town and five goals in a 7–0 win against London Bees. Following the 2015 FIFA Women's World Cup, Reading accepted an undisclosed transfer fee from Chelsea and she completed a move in July 2015. It was reported that the fee of between £40,000 and £60,000 constituted a British record, although Chelsea denied this was the case and Kirby was not aware of the figure.