None of these translations are very good. Foreigners don't understand Confucius at all. Standing at the age of 30, at least means having your own career, or standing firm on the road of life. Being not confused means that you can have a clear understanding of things ... so I suggest the following translation (as Confucius never said, how about 70):

At the age of thirty, I started my own business.

At the age of forty, I can judge everything.

At the age of fifty, I knew my destiny.

At the age of sixty, my ears adapted to nature.