How can you tell when you are grown up?

When does the transition occur? Is there a specific point? Is it the same ‘point’ for each of us? Is there such a thing? Could it be that none of us do, and that we are just on a track? Did older cultures handle this better? With their ‘initiation’ ceremonies and such? Do such ceremonies still occur, but in secret? And perhaps most importantly, do you want to ‘grow up’?