I was afraid of that response. It's 21 weeks old as still is not crowing. Do silkies take forever to crow? Here is a side view and it sitting in the nesting box.
With a huge comb like that I would think cockerel. Also it's not unheard of for one to sit with the female to encourage her and even take over warming the eggs while mama leaves to eat, drink & poo.. I do hope you will update when you know for certain.
I will definitely keep all of you posted as soon as I am certain. I'm crossing my fingers for a pullet because I can't keep roosters where I live. Have a good night.