Never too late. It's absolutely worth it, and at 30 you're hardly too old to do absolutely anything you want as far as career changes.

But I think that way beyond the technical training you will get in CS, the true value of a university education is taking classes in a wide variety of fields: literature, sociology, biology, math, physics, foreign language, history, etc....and having a chance to talk to other smart people about what you're learning. As someone else recently said, the intersection of the humanities and engineering/sciences is a wild and rewarding place to live.