I know of a close male friend who entered NUS Engineering (1st ) degree FULLTIME at age of 29. He was formerly from poly and had worked for a few years. He is happy with his job in a MNC now, paying way above his poly classmates who did not advance (in their education).

It's never too late to study, or broaden your knowledge.

As for if it is worth it or not, you may like to ask what' the objective?
1) To be rich fastest, spend the to beautify yourself and then snag a 'golden turtle'.
2) To earn more $$$ fast by yourself legally, then consider jobs in the insurance or housing industry. [Sales type. Must learn how to "smoke".]

As for change of career path, reality check is required.
E.g.: if you had diploma in Mass-Comm, and now want to take degree in Accounting->CPA, be aware that the starting pay/rank is entry level. Thus, if your last drawn is S$3K, then prepared to start all over (in your new career) as entry level ($2K). Are you prepared?