I will be turning 23 soon.
Five years ago I've made a decision that I will surpass the bad condition I was in back then and that I will work hard to improve myself and my mindset as much as possible.
I believe maturity is a subjective thing and it's based on the emotions and challenges you go through life. I've met 40-year-olds who were acting like 18-year-olds and 18-year-olds who enrolled in the army and at 22 developed such great self-discipline that others can only dream of.
Based on these thoughts, what you need to focus on the most is internal growth. Don't go adding unnecessary things around you, instead develop inner toughness.