You did it, I did it, we all did it. When we were kids, we'd always at some point just start randomly digging in the backyard.  Sometimes it was to see if you could find hidden treasure, or coins, or to bury something you weren't supposed to have.  But I'm sure we all also did the thing  where you dug just to see how far you could get.  And I'm sure somebody made the joke that you'd better stop or you're doing to dig your way to China.

Now, as an adult, I have this thing called the internet.  So I can finally answer the question, would you end up in China if you just kept digging?  Turns out, well, no. I know in reality we'd probably dig for a while until we hit rock, and if somehow had a magic shovel that could get through that and the,  you know, the burning hot magma ( I looked it up, it's called magma until it comes out onto the Earth's surface, THEN it's called lava) and turn up on the other side, you would be FAR from China.

https://www.antipodesmap.com

Yep, there we are, somewhere between Africa and Australia.   Our latitude/longitude in Sedalia is approximately:

Coordinates: 38.709831, -93.229551 (38° 42' 35.4" N, 93° 13' 46.4" W)
Which, directly below us on the other side of the world, brings us to this: 
Coordinates: -38.709831, 86.770449 (38° 42' 35.4" S, 86° 46' 13.6" E)
Great.  The Indian Ocean.  Just what we need, right?  Tons of sea creatures looking to kill you.  So, sorry kids of Sedalia, you're not going anywhere when you dig in your yard.  And flat earthers, hollow earthers, etc.... well, you can figure out your own theory. 
If you want to find out more or play around with it, you can always check out the map here.
Diggingly yours,
Behka