Welcome GB Khalsa! I have never made fermented Bulgar cheese, but I have made fermented oatgurt (from raw oat groats) and also homemade vegan yogurt from homemade almond milk and coconut milks. I knew mine was finished when it took on a sort of sourish tangy flavor but still tasted VERY good. I had to keep my oatgurt and my yogurt at a temp between 90 and 110 degrees Fahrenheit. For my oatgurt, I placed the jar of oatgurt mixture over a heavy cookie sheet that was over a heater in the corner of my kitchen and that seemed to work. I tried the warm oven approach for my homemade vegan yogurt but it didn't work very well. I recently purchased a yogurt maker that keeps a steady temp of 110 F and that worked beautifully! I would think 65 F would be too cold? Do you have it in a draft free place?
I am intrigued now by this bulgar cheese! I may just have to put that on my list of new things to try.