Jessica is 15 years old and spends most of her energy wondering who she is and what kind of person she will become. erikson would describe her as facing the crisis called

It is called identity versus identity diffusion. Pre-adulthood is the time of life amongst adolescence and adulthood. As indicated by therapist Erik Erikson, young people experience the psychosocial emergency of character versus part perplexity, which includes investigating their identity as people. 
Commonly, it is the piece of pre-adulthood when a man has not yet completely understood their social character or characterized their identity attributes - and they are not currently looking to.