I have bipolar 2 disorder and borderline personality disorder and i'm suffering from short term memory loss . is there long term effects on the brain with bipolar 2 disorder and what age will i notice?

Not surprising to experience cognitive symptoms associated with your psychiatric diagnoses, as this is secondary to your emotional issues, and would not be a persistent problem once your disorders are well controlled. Would wonder about your sleep pattern disorder, as a contribution to your "memory loss"?

The emotional disturbances of bipolar disorder and borderline personality disorder can reduce attention. Also, the trauma, doubt and self esteem deficits of borderline P.D. may reduce memory. At times, severe depression and trauma can shrink hippocampus in brain affecting memory. With borderline or bipolar meds of benzodiazepines or gabapentin if prescribed can wreak havoc with memory! Stay safe!