If I do lose my hair, it'll be because of my mom's side. Her father and brother both lost their hair, though my uncle not quite to the extent of my grandpa. The whole "hair loss comes from the mother's side" is BS. My uncle is a prime example. His maternal grandfather had a full head of hair until the day he went in the ground and no one else on my grandma's side lost their hair, yet my uncle did. But, everyone on my maternal grandfather's side lost their hair.
The one thing I have going for me is everyone on my mom's side that did lose their hair, were all thin no later than 25. Just about all showed signs by 21 or so. It everything remains the same, then it looks like I'll be taking my dad's side in the hair department.