How come I can't grow a beard?

I'm 18 years old, don't know if this matters but I'm 6 ft 1 and 136 Ibs. I don't get stubble like you'd see guy have after shaving a beard, I just get hair above my upper lip and on my chin. I have absolutely no hair growth on my face cheeks, how come? I would like to have a neat, tidy beard
Update: Just to clarify genetics. All of my Uncles, my Grandfather and my father can grow beards as well as my older brother
Update 2: Just to clarify genetics. All of my Uncles, my Grandfather and my father can grow beards as well as my older brother
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