I started playing when I was 20 and a student and I wish I had started earlier.
Shortly after getting my business studies degree, I fell into the print industry, where I've worked for 8 different companies since 1984 to escape the redundancy axe (with varying degrees of success).
If I'd the chance to do it all again, I'd have practiced harder on the bass, listened to the people who told me I was good at it, and been true to my creative side and tried to make a career out of it. I'd probably have been as poor as a church-mouse (ie, marginally poorer than I am now), but I'm sure I'd have been happier.......