In fact, you don't have to pretend anything too deliberately. I think you should let people feel your sincerity. I personally attach great importance to "sincerity". In addition, it is also important for you to think about whether you are selfish or care too much about yourself and not enough about others. Everyone wants to be cared about! I have a friend, she will be very enthusiastic to help, and take her friends' affairs as her own, which sometimes makes people feel very warm. It's good to try to improve yourself, but don't be like a child. You also say that you are 20. Think about things as comprehensively as possible and think more about others. Slowly, you will find yourself more mature.
It's all my personal thoughts, and it's not official, hehe!