Wow.... You got me glued with each word, sentence and paragraphs. You broke down the distinct between age and maturity bits by bits in a way that would sink in.
Honestly just like you said, maturity is a choice in the sense that people either choose to analyse and learn from their mistakes or to apportion the blame on others, pass through life or allow life to pass through them.
It's a matter of choice that speaks loud at the end of the day.