"twenty something"

When you’re 20 you’re simply
Knocking on the door of your twenties.
When you turn 21 you’re invited in,
But only to the foyer.
When you’re 22 you’re ushered to the table.
At 23 they begin serving you the appetizers.
At 24 and 25 you’re served the main course.
At 26 you learn how to cook the food.
At 27 and 28 you try cooking it on your own.
At 29 you accept the results of your efforts.