Where's my more specific reason?
"There is just no pleasing ya, is there? Everything has to be just so."
There's not enough information to give a 'specific reason'. You said it was confirmed to be only 13 episodes, if you believe there is no reason for it to be 13 episodes then there is no reason not to think that there will be 26 episode. Because of the lack of information the 13 episode thing could still turn out to be a rumor.
But if you believe there are only 13 episodes then there are other explanation for this other than it being cancelled. And yes, it being cancel is also possible, but imo the least possible explanation, unless you can give me a good reason why they would cancel it.