Older Sibling in My Care

My older sibling is in my care.

Does anyone else experience a similar situation?

My sister is 13 years my senior, yet, due to untreated seizures from the age of three to the age of seven, she has the mentality of a five- or six-year old.  I'm the only living relative in our immediate family.  So, I gladly choose to care for her, of course.  This is not the problem I've been having with her for two years.

She has mild retardation, and it's sometimes difficult to communicate with her.

Are you in a similar situation?

If so, please respond.