too soon to go on propecia?

[johnathan]

Hi, I am a 20 year old male with a father who was balding at 20. I've noticed thinning at the temples and I think at the very front and taking the advice that the earlier you go do something about it the better, I went to something called the Boots hair retention scheme which is basically just a way to access propecia. I was told that because I am a NW2 I am not eligible for propecia and I would have to come back as a NW3 or 'worse'.

So what I'm wondering is:
Why would this be the case?
Is propecia beneficial at this stage?
Could propecia 'stop' me from becoming a NW3 (I know it doesn't work forever)?
Is this going to be something that is a roadblock wherever I go or might I get on propecia as a NW2 via another route?

Thanks