Is this a serious mental health diagnosis?

Letter from my psychiatrist:

This is a 16 year old girl with mild to moderate depressive disorder and traits of emerging borderline personality disorder, being treated with fluoxetine 20mg. She has a 2 year history of chronic feelings of low self esteem, poor self image, dissatisfaction with her appearance and eating disorder. She has lost weight by limiting intake, increasing exercise and on some occasions, has got into a binge-purge pattern. She has also managed her mood by self harming behaviour though less so recently. She is an intelligent girl who sets herself high standards and is critical or herself, compares herself unfavourably to others and tends to predict that others will judge her unfavourably. I think this has contributed to her low mood, some degree of social anxiety and led into her eating disorder and self harming behaviour.

How serious is this diagnosis?