Derry Girls: Can you guess the ages of the actors in the hit Channel 4 series? Derry Girls is set in Derry in the 1990s. In pictures: Derry Girls Fans of Channel 4 comedy series Derry Girls were shocked to learn the real age of actor Nicola Coughlan (Clare Devlin) this week. This got us thinking - what are the real ages of some of the other main stars of the series (see below)? Supporting local theatre this Christmas!