Lots of good advice here (and some not so good).
I would only add: consider a deferrment- you can request one. It's more than a gap year decision, it's a place at uni guaranteed. In that year you can work, fly, and get a sense of perspective.
You're young enough to 'waste' all your dosh on flying- you have no other responsibilities. That might all be different in 5 years, family, house etc.