Coin Flipping Coins

If time travel is impossible, how are we supposed to check that coins have been flipped or even if the coins exist? Well, i mean, i think we can tell that coins exist without time travel needng to be possible. We know things about like likea zeb ere, the coin with heads on both sides. The reason i know that if i'd clipped that i would ve land heads is because the actual coin i'm holding right now and my hand has heads on both side. That's it. I don't need to travel to a possible world in order to tell which way i would have landed in that world. And if it's no way of saying which way it