I have a question about baldness?

I'm 18 years old, and am concerned about going bald. My dad's hair receded a little, and then stopped without use of products. My mothers father had a full head o' hair til the day he bought the farm. My paternal grandfather started balding at about 40 , till the cancer got em. My hair is super awesomely thick all over, but my hairline is definitely different from when I was 15 or so. The corners are farther back than they used to be, but the middle is the same. I'm completely cool with going Bruce Willis if it has to come to that. Thanks.