I studied law for 5 years, hated it and now study GEM at Warwick. Only in 1st year but so far its the best decision I ever made. I was damn good at law, which is incredibly cocky but point is I could have been very successful (and most likely far better paid!) but I didnt see the point in embarking on a career that I wasnt excited about even at the start.
It is a tough route, especially since I've started with no science backing - Warwick doesn't even require A levels for sciences - but incredibly rewarding, interesting and you'll find a varied bunch of people on the course who can help out and empathise with the constant feeling of knowing nothing!
Make sure you want to do medicine for its own sake and not because you dont fancy the job youre going into. In other words get experience before jumping in. As you clearly realise, it's a big commitment. Age shouldn't be a factor, we have 30/40 year olds in my year, nor should debt (though make sure you can afford the course). End of the day you'll have basically a guaranteed job which is reasonably paid and anyway, we dont do it for the money. Which is lucky given our friend Jeremy is taking it all away in the new contract...
Give a shout if you want to know anything specific about my experiences/entry etc.