Born in 1857 Sarah was the first child born to Freya Trelawney and like pretty much all of Freya’s children she is illegitimate. At the time of Sarah’s birth Freya still lived with her parents so the first few years of her life were likely relatively comfortable and this continued through the birth of Freya’s next five children. In 1866 the family was disowned and things went from shit to worse from then on. Sarah attended Hogwarts and probably at least achieved OWLs but did not get NEWTs – her profession should reflect her level of education and she can live in Hogsmeade or Irvingly. If she is actually married is up to you but she is at least co-habiting with somebody and keeping up the pretence for some reason. Her rep should be no more than six and, like her mother and sister, she is prone to romanticising things and not always making the best decisions.