So what do you guys think?

Yeah, so this has already been brought up, but IF she did have a cell phone who would she be talking to in 1928? Did someone else have a cell phone back then with her? Where were the cell towers? Maybe the phone's signal traveled through time also, into the future where someone else had a cell phone? :P

And, from what I have gathered thus far time travel IS possible, but probably not the way you think. Since there is a relationship between gravity and time if you were to travel far enough away from Earth, time for you would slow down while on Earth it would continue to run at normal speed. So if you went into space really far away and then came back to Earth you will essentially be in the "future". This would be in the sense that everyone/everything will have aged faster then you during the time you were away from the Earth's gravity.

Time travel into the future would be a much more difficult task and may not be possible at all.

And now concludes today's science lesson :)