Clients slow down when connecting to my PE World

Hello, I have a world on my Samsung Galaxy S4 that has reached about 150.2 MB in size which I suspect is due to some exploration very far away from the world's spawn. When anyone connects to my world, whether in MCPE or the Windows 10 Edition, they experience very high amounts of lag. It's not a kind of lag that eventually causes a disconnect, but rather they won't be able to see my movements right away, nor will they be able to place blocks, open chests, or interact with other things until after a large amount of time passes.

Eventually, they'll reach a point where they see an image of where I used to be and see me slowly making my way to wherever it was that I was going. Clients can also hit that image and I'll feel the effects in real time. Also, they may eventually be able to enter a chest, but not after being able to "open" many other chests. In the picture I attached, there are several chests that are have been opened by the same person, and they are passing through a door that is open on their end, but closed on mine.

On my end, I can see all of the movements of the people connected to my world in real time. For instance, someone may step on a pressure plate to enter a door. The door will open on my end, but not on theirs and it'll appear to me as them hitting an invisible wall, while on their end the door never opened in the first place. In other cases (as in the picture), I'll see several chests that have been opened by one single player.

None of these effects happen on smaller worlds such as the Story Mode map that was released not too long ago. So, is this a problem due to the size of my world? If so, is there any way to decrease the size of it? I wouldn't mind discarding the parts of the world that are far away from the world's spawn, or the loaded sections of the nether. Those areas aren't needed really.

Oh, and by the way, the overlay on the screen isn't a mod or anything like that. It's just a scene that I made using Tasker that appears as I'm using Minecraft so that I can see my phone's battery level and the time. The game itself isn't being modded.