Hi. This thread is pretty old now (not as old as me though!) but still thought I'd throw in my two cents worth since this seems to be a recurring topic - in fact, I posted a very similar question to the one asked just a couple of years ago when I was 54 (I'm now 56)
My situation was slightly different to yours but I think the same basic principles apply. I was involved in the professional music business for virtually all of my working life, and when I became what I considered was a bit long in the tooth for it, I thought I might begin lecturing/tutoring new generations of those hoping to enter the industry. But I felt that I would stand little or no chance of getting such work without formal qualifications to go with my experience and hence I applied (and got accepted) for a place on a BSc (Hons) course in Studio Recording & Performance Technology. I skipped the first year of the course under whats called the APEL scheme (Accreditation by Prior Experiential Learning) and was extremely apprehensive about what was in store, but I need not have worried: I have had a blast with fellow students and lecturers alike, though admit to having worked extra hard to do the absolute best that I could.
This month my hard work has been rewarded with a 1st class degree and I have even won a prize for best performing final year student in the department.
Best of all, as a result of my experience and the contacts I made in uni, instead of going into full time lecturing, I am now fairly confident of winning a PhD studentship - which is way beyond anything I originally hoped for - and the fact that I will get paid a tax free stipend of £14k for it is a fantastic bonus.
I still reckon I will have a few more years work left in me even after the three years this is gonna take, but it will have been worth it just for the exerience and the satisfaction it will afford me even if I dont find a job 'because of my age'. I therefore wholeheartedly echo the views of other posters - If nothing else, it will be a great experience, and like some others have already said, one rarely regrets what one has done - but rather the things you didn't do. Go for it & Good luck!