Maturity is a state of mind
MATURITY IS A STATE OF MIND:
Maturity is when we learn from our experience and improve our mindset towards situations and people.
With our experiences of life, our perception and outlook changes. Things that matter much to us slowly don't bother us anymore. We learn that things will happen, plans might not work and other people might act in certain way that we don't approve of but instead of being sad and miserable, we learn to accept it. We embrace many situations in life and ignore even people who try to prove us wrong because we realise our mental peace is more important than anything that may disturb that peace.
To have maturity in your thoughts, you must understand and embrace that people don't think and feel the same as you do.
There will be people who will always challenge you. Many times it is better to not prove your point even if you are right because they are not worth it.