Sophie Westbrook is the only child of Margot Westbrook and Eric Casper in Lilsimsie's Westbrook Legacy. She is, in technical terms, the Generation 3 heir, though did not get her own season as Kayla skipped the 3rd generation.
Sophie was born in episode 33 of season 2 of the Westbrook Legacy(named "BRAND NEW BABY").
Her childhood was rushed in Kayla's want to end the series soon to start the new series.
In the first episode of season 3, she is the mother of the main protagonist, Tiana Westbrook, and the widowed wife of Jamie Westbrook.