I love stuff that deals with time travel, especially traveling to the past to prevent any future disaster. I would so love to be able to do that myself.
Unfortunately, real life physics as we know it means time travel (at least to the past for the purpose of changing it) is actually impossible because it would almost always create a paradox unless you were supposed to travel back in time and inadvertently cause the very thing you were trying to prevent. Here, I'll let a scene from Avengers Endgame explain it:
Basically, even if you do change the past, the best you can do is create a new branch, an alternate timeline that you may or may not get to live in while the old timeline is unchanged and remains distinct.
I think if I had a time machine, I'd rather use it to skip to the future so I don't have to wait to enjoy all the shows and games I'd want to experience before I die. Who knows, there could even be technology that does allow people to travel backwards in time, paradox-free and within the same timeline.