I just checked, it should be there, but perhaps something else is the issue. To clarify, there are multiple options that show up at the bottom of your screen when the game is in the "visual novel" mode, so to say. You can quickly test this by starting a new game just to check.
6 days ago(+2)
Okay, so the option not being there indicates that the game doesn't recognize you being on a mobile device. I will try to look into this, unfortunately not much you can do about it, I think, apologies!
5 days ago(+1)
Might be a tablet issue, or maybe unique to the kindle fire haha. Can't imagine too many people are playing on this. No apologies needed, the game works great and the low performance mode was perfect for my device!