[iwantaskyline]

^

Spoiler!

Your GF is wrong IMO.

Time is a flat circle in this movie. Time to the aliens is the present, past and future -- they view time all at once. So Amy Adams wasn't really "seeing" the future, she was living it which means she wouldn't be able to change the future.

A few examples to back this up:

-When Costello tells Amy that "Abbot is in death process" -- that's not past, present, or future tense. Abbot already knew he was going to die when he showed up to meet them when the bomb was planted.

-What the aliens said to the Russians who misinterpreted "There is no time, use weapon". They're telling the Russians time doesn't exist and to use the weapon which is the language they gave them.