By the age twenty, your main personality traits should be well established.  However, this does not mean that you will not continue to change.  According to the psychologist, Erik Erikson, personality develops throughout life as people meet a series of challenges.  He divided life into eight stages.  Each stage presents a different challenge for you to work on throughout your life.  When you successfully accomplish the challenge in one stage, you are better prepared to meet the next challenge.

Develop Trust - A baby depends on other people to meet its need for food and sustenance, hygiene, and affection to it.  If the needs listed are meet, the child learns to trust others.  If the needs are not met, the child learns mistrust and may withdraw from society, other people, and even their parents. 

Learn to be Independent - This is the stage when young children learn how to do stuff by themselves.  They start to gain control over themselves.  They learn to walk and understand what potty-training is.  If children fail to master these tasks, they begin to develop self-doubt.  If their efforts are ridiculed, they may feel ashamed of theselves too.

Take Iniative - During this stage, children start to plan.  They begin to develop a sense of what is right and wrong.  If children are harshly scolded for poor initiatives during their growth, they may feel guilty, unworthy, or resentful towards their parents or teachers.

Develop Skills - Children will learn skills they utilize as adults.  They will learn how to help their parents, how to earn good grades at school, and how to get along and make friends with other kids.  These skills make children feel competent, or capable of achieving their own goals. Without skills, a child may feel like a failure.

Search for Identity - Being a teenager, your challenge is a search for your own identity.  You begin to question who you are and what you want to do with your life when you grow up.  This search leads some teens to try new experiences and to behave in rebellious o disrespectful ways.  Other teens focus on shaping their identities to go along with the standards already set by their family and society.

Establish Intimacy - As a young adult, your challenge will be to establish close bonds with others.  If you learn to make commitments to other people (like getting into and maintaining a relationship), you will have their support as you face the other challenges remaining that lay ahead.

Create and Nurture - Young adults need to stay productive and creative in all parts of their life.  During this stage, these adults get a lot of satisfaction from helping younger people learn and grow to become successful by following their examples.

Look Back With Acceptance - During their older years, people often tend to reflect on their past lives.  Some accept the choices they made during their earlier years, while many others may regret the opportunities they had missed during their years as young adults and mature adults.