barshaker - I've been flying regularly since I was 12. I started the licence when I was 14.
To be honest, apart from the fact it's nice to get cracking on the licence, and be able to log the time 'propa, I wouldn't recommend starting the licence until you're nearly solo age.
Unless you're going to be flying regularly, you'll spend a lot of time and money going over things you've done before.
Once you've soloed, you can do everything, including the GFT.
tKF