I started thinning at 21, and not many people aside from my stylist noticed until I was somewhere around 24-25. So, it took 3 years to really notice.
Some people lose their hair almost overnight- a buddy of mine that said I wasn't losing my hair, said he lost all of his within 6 months of the slightest hint of balding. Took me 3 years, since I noticed and was probably going prior to that.
I now shave my head, and I've been happy with it as most others seem to like it as well. The power is what you give it.
My entire family has hair, on both sides. My grandfather, who is the thinnest, still has more hair at 80, than I currently have sans the shaved head.
Go figure.
