Sheila Birling is presented as an influential character from which Priestley can voice and impose his viewpoints of social hierarchy as well as gender inequality in a way which the people can relate to as if Sheila is capable of change, so are the people.
At the start of the play, Sheila is presented as a conventional Edwardian woman who conforms to society's expectations. Priestley introduces Sheila as "a pretty girl in her early twenties, very pleased with life and rather excited" to convey the typical attitudes of a middle class Edwardian woman who is sheltered from the realities of the harsh world and also the struggles from which the lower classes like Eva face. The fact that she is "pretty" connotes the frivolous convention of Edwardian women but also indicates her naivety which is further developed when Priestly refers to Sheila as a "girl" rather than a woman. Her immaturity is reinforced as she is "very pleased with life and rather excited" suggesting she is content with the suffering that occurs in the society around her that she is so far oblivious to as she holds the same myopic and self centred views of her parents who don't value "community and all the nonsense". Consequently, Priestley may be highlighting how Sheila is unenlightened to socialism, something which was very common among young higher class individuals due to the influence of their parents.