Originally from Greater London, Mattheson earned an undergraduate degree from Bournemouth University and completed a master’s degree at the University of Chichester while working full time at Tottenham Hotspur.
She began her professional career with Southend United, then a League One club, before spending seven and a half years at Tottenham. During that time, Mattheson worked five years with the men’s academy before transitioning to the women’s first team, where she remained for the remainder of her tenure.