I chose the Uni option, and joined a UAS. That was the best decision for me, and I don't regret it at all, but you have to decide what is best for you, so I'll just tell you what I've done, rather than saying what I think you should do.
I went to Nottingham Uni and did a maths degree at 18. Joined the University Air Squadron when I got there, which was great - 3 years of brilliant flying, and great people. Still only 21 and I graduated from Uni, had a degree and 120hours on the Bulldog having completed the RAF Elementary Flying Training.
During my final year and the year after graduating went through a few selection processes for the airline - BA twice, bmi twice, AFT, etc. Wasn't successful unfortunately, but luckily I had my degree to use. During this time I also did my PPL, which was very quick after the UAS flying. Also applied for a few graduate type jobs to start earning some money while I kept applying for the airlines. I took the first one I was offered with DERA, working in the Cockpit Systems area - aviation related, and very interesting and varied work. Then the airline recruitment dried up quite a bit, so I was glad I was in a good job. Now been working in this job, now with QinetiQ since we were privatised, for getting on for 2 years.
Ok, so I'm still not in a flying job, so you could say that I made a wrong decision somewhere along the line - but I don't know if it would have been any different if I didn't go to uni, but not having the flying job I know I'm in the best position now that I could be. I'm now 24, and have a good degree for a good university. Had 3 years of great flying with the UAS while I was there. Now have a PPL which I still keep current just flying for fun. Have 2 years of experience in mainly aviation related research and development work.
I still have an application in with BA, and am half way through the selection for AFT's full sponsorship - so if either of those start going again soon, then who knows, I may still get that flying job yet. If not though I'm enjoying what I'm doing now, and have a lot more opportunities available to me in non-flying careers than someone who didn't go to uni.
Which ever way you decide to go, make sure you commit to what you're doing, and make the most of it.