Look at this diagram
As shown in the diagram, my children had been staying home for a year due to Covid-19. Within that year, they had never been sick.
A week ago, they started going back to school. A first few days within that week, they were well not sick but now they are sick.
Can we use this structure?:
Past perfect or past perfect continuous + since a point of time in the past + until another point of time in the past
Is it correct to say "She had never been sick since she started staying at home until she started going to school"?
I have a feeling that "until" should be replaced by "by the time"
"She had never been sick since she started staying at home by the time she started going to school"