FF,
As a final year bursar on a UAS i empathise greatly with your situation. If you WANT to go to uni, then go. If you're not sure but are sure about being a pilot (and hopefully FJ) then apply for direct entry.
The FJ intake is shafted at present but, if you're good enough - you'll get it. The benefit of being on a UAS is that you'll get an indication of how good you are before you've had the hassle of going through Cranhell. If you fly like a chimp, you can carry on colouring in at uni, if you happen to be **** hot then you can always bin uni and apply DE.
I went to uni in a very similar position to yourself and joined a UAS. Had a great time but after 2.5 years i've had enough and my degree has suffered due to the pressures of completing EFT competitively and getting pissed with the UAS.
My grievance is that if i'd gone DE, FJ would have been in the bag and hopefully still is, but my decision to "have a degree to fall back on" could have seriously altered my career path i.e. no FJ for me!
As one of the other guys said, you can't predict anything or hang on what anyone says. I'd get in there ASAP and work my tits off.
Also, NB that IF you get a pilot slot you'll have really long "holds" and you could get involved in the in service degree program.