The movie uses the bootstrap paradox model of time travel: there is only one timeline, and events can’t be changed, because any attempt to change the timeline had already happened. She only was able to see her child’s future because the child was born. If she had made a different decision in the future, she would never have seen the visions in the past.
See also: Terminator 1 (not the sequels,) Predestination, 12 Monkeys, Tenet
The movie uses the bootstrap paradox model of time travel: there is only one timeline, and events can’t be changed, because any attempt to change the timeline had already happened. She only was able to see her child’s future because the child was born. If she had made a different decision in the future, she would never have seen the visions in the past.
See also: Terminator 1 (not the sequels,) Predestination, 12 Monkeys, Tenet
The ending to 12 Monkeys is my favorite time travel movie ending ever.