I'm a new poster but i think that i have some good advice.
If you are young, live in Britain and love aviation then the best thing that you can do is to join your local ATC (Air Cadets). I have only been in for a year and a half and at 15, i have:
Visited many RAF stations.
Flown a Vigilant glider solo.
Flown a Grob Tutor many times.
Flown in a VC10 with Tornafo F3's refueling.
Flown in a Nimrod.
Flown in a Hercules.
Flown in a Sea King rescue helicopter.
Watched Tornadoes and Hawks taking off while waiting for these flights.
And Much More...
Personally i don't think that i can give anyone any better advice than this.
Sorry if this is the wrong place to post this but i just wanted to share some of my experiences.
Happy Flying.