I’ve seen this question asked all over the internet, and all I can really say is “What a silly question!” I have to imagine that to the young person, entrepreneurship is seen as a “older” persons thing. And I have to also imagine that to the older people, it is seen as a “younger” persons thing.
When I feel down about the slow pace of entrepreneurship, Colonel Sanders comes to mind. The chicken mogal was someone who worked his whole life and was a successful entrepreneur in his 40’s. But the KFC brand only became iconic at during his 60’s. Here is a book on Amazon:
In my opinion the answer to the question of the average age is that there isn’t an average. Or rather you can become an entrepreneur at any age. Get off your duff and get to it! Here is another article that helps provide food for thought.