Answer:
Formal Operational Stage
Step-by-step explanation:
The formal operational stage is characterized by an increase in the ability to think abstractly and develop self-centeredness, and also to reason, contend and strategise. The formal operationalstage begins at approximately age 11 and lasts into adulthood.
Donna's new hair style was not all that she anticipated, her mum tried to convince her, but she feels that her mother couldn't possibly understand how she felt, this shows Donna is able to think Abstractly and doesn't depend on the opinion of the mother.
Other important skills that develop at this point are the ability to effectively prepare for the future and think about hypothetical scenarios.