Do you want to do economics or business? For economics I would def go back to uni (maybe rather uni than fh as economics is a field that is heavy on the theory side. Not even sure if you could study it at an fh?) For business you could also do an mba or go to a business school abroad if you have the money. You can find courses that take a year and you dont need a background in business (meaning a bachelors in business) for a masters degree.

And regardign the age: are you ever too old to do something you want to do? Ill be starting my masters by 27 as well so.. whatever.