Adcom are more interested in what they can learn about you from the
example (and your response to it) than from the age of the example.
As people get older and more experienced, they are often faced with
more complex situations, and use their experience to deal with them in
a more nuanced manner. Using a more recent example may allow you to
present your decision making at a more sophisticated and mature stage
of your development.
However, using an older example that more profoundly affected the
direction of your life might help adcom see the full context of the
example and help them better understand you as person.
Basically, there isn't a categorical answer either way on this - you will have to use your own judgement.
FF