Maturity is not measured by age.
Nor is it proportional by age.
Maturity is a state of mind, where people outdo, out think the average. Having a sound long term plan defines maturity. Having the preparation and anticipation of the future is maturity.
Maturity is not a stage you reach by living the years in your live. It's a perspective of thought. It is enlightenment. Not just doing the right things. But also doing things the right way.