@Remy has time travel figured out, please let me know via PM when your machine is ready. I want first dibs on the first journey....I'm serious
If the theory of parallel universes with multiple timelines is correct, time travel would be a possibility. The idea could mean that in some universes, the asteroid that killed the dinosaurs missed Earth.
Marvel comics has had mutliple universes for decades now. So the movie is just borrowing and expanding on ideas from comics albeit not exactly.