You can create a global script for your score ! It’s probably one of the solutions you can choose. Surely someone else will come up with even a better solution but I want you to do the following as it’s also a way to deal with it :
Once you have made your global script just declare the var count = 0 in it instead of declaring it in your world.gd
Now you have to go to Project > Project Settings from the menu and select Autoload tab. It will be the fourth tab, you’ll easily see it.
There you will have an option of Path. Select the folder icon in front of it and choose the global script that you just created in Step 1. There will also be an Option of Node Name where you can give a name to your singleton. I recommend naming it to global. Finally hit Add