Hi Vinc
well, my father was already full bald by 30 y.o. (have a picture with me when I was 6 months old and he was N7 then !) so I was very self-conscious about my incoming baldness since high-school. I remember colleagues in high-school and college telling me I'm going bald and if I'm going to do anything about it. I accepted it as I didn't know there was a cure for it and didn't do anything except for keeping my hair short.
So short answer is that I'm balding since I was a teenager (25 years ago); to tell you frankly when I was in high-school I thought I was going to be N6-7 by 25, but I guess my alopecia wasn't that aggressive.
My brother who is much younger than me is already N6 ...but he kept long hair during all high-school & college and didn't take proper care so I guess this didn't help.
Initially I was thinking about transplant, this is how I discovered this website, I was looking for doctors
But then I read that you have to go full bald before any surgery otherwise your old hair will fall and new hair will look patchy and well, you know the rest.
So I'm trying to maintain it like this for as long as possible with this regimen and if I can keep it up until 55 let;s say then after that I won't probably care too much
But I guess 15 yrs more of maintaining is probably too ambitious...we'll see when Propecia effects starts to wear off