Yes, she felt more fulfilled nursing people and that accepting the offer may not be as great as she would expect. We see a panel of her caring for Harue and a birdcage which hints that Harue's situation as a woman in a wealthy household is more of an entrapment than freedom. I see Michiko feeling sad still is because it's still a hard decision between guaranteed "safety" and wealth over her current job and also that her connection to Harue is essentialy cut with this decision.
Wow? I don't really quite understand the ending? Why didn't she accept the offer? Because she felt like her purpose in life was nursing people? Then why did she look so sad throwing away those dahlias....??