Sheila Birling?

Priestley describes her as "a pretty girl in her early twenties, very pleased with life and rather excited," which is precisely how she comes across in the first act of the play. In the second and third acts, however, following the realization of the part she has played in Eva Smith's life, she matures and comes to realize the importance of the Inspector's message.

sheila birling is presented as a young girl who doesnt know right from wrong as she is getting engaged in the opening scenes when she shows her mother her ring but later on in the the play we see her character change, she realised what she has done as well as her family but she gets angry with her parent because they have not seen eva smiths death as their fault.