Good morning wannabe!
Of course young people of your age have a different biological clock, about three hours behind the adults....schools are beginning to adjust to this fact!
I recommend you arrive at your NEAREST gliding club, about 9 or 10 am, and ask anybody around who is the duty pilot ....or launchpoint coordinator, whatever they call themselves at Cambridge! Say you would like to learn, and would be willing to help out in any way. See what they say. They will have all kinds of discounts for young people, most clubs do, even London Gliding Club has a very good program.
Talk to other club members, just get a feel for the place. If you rolled up to my gliding club, they would sell you a winch launch for £45 or £50 pounds, which would include 3 months membership, so after this first day, a winch launch would only cost £8. And we fly 7 days, weather permitting. A lot of smaller clubs fly only on weekends.
However, it is not so close to your home....so check out Cambridge first of all, you may find old pilots, but they should be pleased to welcome a youngster, ESPECIALLY if you say you would be pleased to help rig a glider....
If you do begin helping with the gliders, make sure you are doing EXACTLY the correct thing.....don't just rush in and start pushing on the trailing edge, for example. You will be especially welcome if you offer to wash the gliders at the end of the day, they do collect insects on the leading edges!
Others have said it is correct to either help get them out, or help put them away. Or you could pay a lot of money to fly power, and get fat instead...!
have fun! we do.