Final answer:
At 14, Lorna is in the formal operational stage of cognitive development according to Piaget's theory, which allows for abstract and hypothetical thinking.
Step-by-step explanation:
Lorna has just turned 14 and according to Piaget's theory, she has reached the formal operational stage of cognitive development. This is the final stage in Piaget's theory, which typically begins from about age 11 and continues into adulthood. In the formal operational stage, individuals become capable of abstract thinking and can deal with abstract ideas and hypothetical situations that require logical thinking and problem-solving skills. This developmental stage allows for handling complex concepts and performing mental operations involving abstract, multidimensional thinking.