Cooldude,
Speaking as a youthfully optimistic aircrew member of the RAF, I can offer you a couple of pointers.
First of all, the RAF isn't like the Army whatsoever and ive had a whale of a time thus far. However, the lifestyle doesn't suit everyone and it needs careful consideration and research before you apply.
Secondly, the RAF has begun to change its policy over the last 18 months or so from one of sponsoring students to go to university before joining the RAF at 21 to one of an 'In Service Degree Scheme'
This scheme is in conjunction with the Open University and allows you to join the RAF at 18 and go through flying training whilst simultaneously studying for a degree in Aviation, Business etc. Indeed, some of your training counts towards your degree. No doubt the RAF Careers Office could help. The advantage to you is that you would leave the RAF with a degreee whilst the RAF would have you in service 3 years earlier - particularly relevant with the wait in between flying courses these days.
If i'd had the option at 18 I would have seriously considered it. In saying that, I took the normal Uni route and had the best time of my life!
Hope this helps
SVK