AWACS
My opinion for what it's worth:
Delay the Commission and go away to university grow older and wiser. After three or four years enjoying yourself and furthering your prospects make an informed decision:
If it's RAF Fighter Controller then convert to a short term Commission. Believe me after a few years of Controlling you will be wishing you were flying. I know, I've been there with the Army. All those nights away from home on Ops will give you the chance to save for your airline career.
If after few years at university you decide to go the airline route start applying for the sponsorships of the time. I know aviation is going through a bad patch at the moment but as we all know it's cyclical, who knows by the time you are 22 they may be crying out for pilots.
Whatever decision you make in the end please think about what you want out of life if it's is both Officer lifestyle and Airline pilot go for the Short Term Commision.
Hope it helps PM me if you want.
Roller