Sienna is an adult, 42 days away from becoming an elder. She is technically unemployed at the start of the game; she is treated as the Horse Trainer NPC until she is made playable, after which she is immediately replaced. If Growing Together is installed, she has a milestone for receiving her first promotion.
Sienna has sentiments with multiple Sims; she and her best friend/sister-in-law Juniper have mutual Deeply Connected and Closer From Happy Memories sentiments. The very same sentiments are shared between Sienna and Don Gooseman, with the addition of a mutual Impressed sentiment. Indicating recent loss, Sienna and her brother Umber share the Friends In A Time Of Loss sentiments. Sienna has an Adoring sentiment towards her brother, while he has a Deeply Connected one towards her. Sienna also Adores her nephew, Wren, who returns a Closer From Happy Memories sentiment. Interestingly, she has an Awed by Lifesaving Hero sentiment towards Roberto Crinkletop, effectively telling the player that the mysterious man has saved Sienna's life somehow.
With Get Famous installed, Sienna's reputation is neutral with a small dip into negative.