Question: My tween has recently become quite egocentric. Is this a problem?
Answer: In most cases, no. Egocentrism is not only a normal part of development, it's necessary.
All tweens and teens naturally experience some degree of adolescent egocentrism as part of their cognitive development. In turn, being egocentric may support their personality development. Egocentric thinking may encourage adolescents to break away from their family and to form unique identities, a process called individuation. This is important because individuation is one of the primary goals - if not THE primary goal - of adolescence.
Egocentric thinking encourages individuation through the two elements of egocentrism: the personal fable and the imaginary audience. The personal fable is an adolescent's belief that he is special and unique. It aids individuation by encouraging the child to think about himself as a separate entity instead of as a member of the family unit. The imaginary audience causes the adolescent to believe that peers are scrutinizing and commenting on his every move. Like the personal fable, this acute self-awareness makes the adolescent focus on himself as a distinct, autonomous being. It also aids individuation by calling attention to social interactions that do not involve the family - even if most of these "interactions" are in the adolescent's mind!
It may not be fun to have an egocentric adolescent in your house. Afterall, who wants to be around someone who thinks he is both extraordinary and being watched? But rest assured that your child's personality will probably be better for it in the long run. That said, do be aware that problem behaviors may arise from egocentric thinking - including substance use, risk taking, eating disorders and vandalism - and be prepared to intervene if necessary.
Vartanian, Lesa Rae. Revisiting the imaginary audience and personal fable constructs of adolescent egocentrism: A conceptual review. Adolescence. (2000). 35(140): 639-661.