Gaining maturity is the daily activity.
There are multiple ways, below is, one of the ways.
We need to learn, How to be calm and .. while learning that, we will get the maturity. How? Because to remain calm, we need to understand the mind and the thoughts! right ?
Once you understand, how mind is not allowing to be quite? you will understand yourself. So observation is the key. Once you understand the behavior of mind. you will know behavior of others.
Another easiest way to gain more maturity is “compassion”. Try to understand others But always Remember to “do the right thing”