I'm sort of in the same situation. Except slightly different - I have to do an access course first (just started it last week, actually) because my poor A levels won't do it alone so I'll be almost 23 when I start year 1, and almost 27 when I have my degree.
Thats a long time, I'm still weighing up whether its worth it career wise because I could earn plus gain on the job skills by working. I've been working full time for three years and I'm used to the income, I enjoy working a lot more than learning. The environments are totally different too and I prefer the professional office environment to the screaming chav kids with no respect or drive and are only there because it seems normal to stay in education for as long as you can by default.
All I want is the piece of paper that unlocks the doors, I've already done the get drunk everyday thing and most of my mates are mid twenties anyway so I'm slightly more mature minded.
Can anyone relate or offer advice?