This article describes what experts define as typical behavior for an twelve-year-old.
A Typical Seventh Grader
Where They Are
The average twelve-year-old is entering the stage in between childish and mature behavior. He:
Is spirited and enthusiastic.Can "stay put" longer and exercise self-control.Develops a growing sense of intuition and insight into self and others.Becomes less moody and may become good-natured around adults.Becomes increasingly self-reliant and self-centered.Is curious but not ready for long-term planning.Has strong desire to be like peers.Where They're Going
At this age your child is learning how to be independent as she undergoes many changes. You can help by encouraging her as she:
Learns to cope with changes.Makes the transition to adolescence.Works on interpersonal skills.Adjusts to peer groups and pressure.Develops her personal interests and abilities.Gains a greater sense of responsibility for her behavior and decisions. 
Brought to you by the American School Counselor Association