...if you are matured enough to make decisions about yourself and your life without supervision,...
This is where age truly shows it's a number. I have also seen men and women whose sense of reasoning or what they do didn't match up with their age. In this case, what can we say?
I know people who are teenagers or in their very early 20s, if you hear then talk, you'll get really confused if they truly are teenagers.
Maturity is not to be measured by age.
Maturity is a state of mind where you can accommodate and handle some certain information, activities and responsibilities in a way that will not please you and everyone around you, like nothing even happened...
It's not determined by age, but by the mind exposure.