You have to expose children to time travel ideas when they're young, before their minds are stuck in 3 dimensions, seeing time as being linear. When I visited a friend recently, I started immediately with this 5-year-old son.
5yrold: Who are you?
Me: I'm Robert.
5yrold: My little brother's name is Robert.
Me: I know, I'm him from the future.
Me: I've traveled through time to spend time with myself and my family when we were young.
He was skeptical at first, but I told him that when the first time travel machines came out in 2022 time travel was pretty expensive, so I didn't make my first trip until 2025. First I went back to see the dinosaurs, but it was hot and hard to breathe, so it wasn't as much fun as I thought it would be. Then I went to see Jesus speak, but I don't understand ancient Hebrew so I really didn't get much out of the experience. So when I had saved enough for a third trip I figured I'd go back and see what my parents were like when I was barely out of diapers. Plus, I explained that even though I was just a young child, I distinctly remembered being visited by myself from the future around this time, so since I was going to take this time travel trip anyway, I might as well take it now.
His parents are cool and played along. They called me "son" and I called them mom and dad. The 5-year-old was pretty skeptical about the whole thing, but it's pretty easy to outsmart a child when they try to expose your fibs. For example:
5yrold: Ok if you're from the future then you know if I'm about to cough.
Me: How would I know that? I'm not here - I'm in the next room.
5yrold: (calls his brother into the room). Robert, watch me carefully and remember if I cough.
Robert(not me): (Nods, watches carefully)
Me: I remember this conversation.
5yrold: So did I cough?
Me: I remember me from the future saying that you wouldn't, and then you coughing just to prove me wrong. So ... no.
5yrold: (thinking very hard) Cough.
Later on we were in the car driving home from somewhere and he really wanted to get home so he could play. The drive would take a half hour and he didn't want to wait. So I told him to just go forward in time to when we were home and he could play right now. Then, he could always come back and do the drive home later tonight. I explained that we don't have to experience the week in a linear order: Monday, Tuesday, Wednesday etc ... that time was all relative and that we could do Monday then Wednesday then back to Tuesday. He seemed to understand this.
After a short pause, I welcomed him back. He said he didn't go anywhere, and I said yes, he went to the future to play, and now he was back to do the drive home. When he said he didn't remember playing, I said that's because it's the drive home now, so he doesn't have the memories of having played yet. Memories are stored in the brain, so if he wants to remember playing, he needs to go forward to and experience a time when those memories existed. But I assured him that he has, in fact, already played, eaten dinner, and gotten into bed.
Anyway I'm not sure how much sense any of this makes to him, but I've got him thinking about time in non-linear terms, so he may one day be the guy to invent time travel.