Best of luck to you Tom - you'll enjoy it. But beware - it's addictive. I first went when I was your age and did the trip on a shoestring (although I have never NOT drank, and havn't been that weight since I was about 9!!). I've been back a time or two since then of course

Many of the members on here go for much longer to participate in
a) the other race-oriented activities (scrutineering, practice sessions etc) and
b)the many social activities which occur throughout the week.
All of which gobbles up a few more euros.
As you will see, a lot of money is spent on booze, flags, booze, food, booze, fireworks, and errr.....booze. And if you are there for a week or more (as some of us are), there's no way you can transport that amount of sustenance from the UK, either liquid or solid.
Put it in your diary for next year - you'll be back.
Del