It doesn’t have to be an in-game counter. A progress bar that tells me how far I’m away for the end would be sufficient.
At first I thought about the letters flying around as kind of debris and tried to click the feather with the cursor (the windmill thingy).
If there were some wavy lines to indicate that the feather is controlled by the windmill, it should be easier to grasp.
Regarding the tutorial, while close to the house some words would make it more obvious. Perhaps an „Today I’m writing you…“ catched earlier and moved to a letter before the feather goes on its journey? (Because having a scene inhouse would be too much effort?)