Not sure if this has ever been revealed or discussed, but I always wondered whether she knew when exactly these two died as she would have only been in her 30's when they passed. Also does anyone know whether she ever sees Obi-Wan again?
It is unclear in what timeline Ahsoka exists
As we all know, time travel was introduced in Rebels episode A World Between Worlds. In that episode Ezra saves Ahsoka from Vader by pulling her from Sith Temple on Malachor, thus alternating original timeline. Later, while fleeing from Palpatine, Ahsoka returns to the Temple, but again it is not clear what timeline is this. Finally in final episode :) of the Rebels, we see her meeting Sabine Wren after Empire collapsed.
Of course, in original trilogy Ahsoka does not exist, and neither Obi-Wan or Vader meet her or mention her. Unless Disney retcons something, she has no influence on Rebellion and Galactic Civil War since her disappearance on Malachor. This leads us to conclusion, no matter how confusing this is, that original trilogy plays out in a timeline without Ahsoka, and that she exists in her own timeline, possibly somehow traveling back to meet Sabine.
Out of universe, because of Disney's inept storytelling, many fans simply choose to ignore Rebels final episodes, and consider Ahsoka to be dead in main timeline displayed in original trilogy.