Hum, I am not sure. I think the mean is correct as you stated, yet not sure about the median, as if it’s symmetrical then I would suspect that C is the mean, mode, and median, right? If not assuming C is the mid point then the mean is not the same as the median or mode.

Not sure about the median calculation, it’s not in my references. I did find this chapter on the distribution that may be of interest.

https://www.worldscientific.com/doi/suppl/10.1142/5720/suppl_file/5720_chap1.pdf

enjoy, Fred