She spread the message through time and space, so obviously range wasn't a problem. However, what she did was what was required to get her to that point, she laid the path she had already followed.
In other words, if she'd changed much else, then she would have changed the events in her own life and made it impossible for her to get to that point, making a big paradox - of the kind we're told always to avoid.
The other explanation of course, is that her puny human brain hadn't got around to working out the possibilities before it started to be consumed.