Who is Baroness Matilda from The Story of the Trapp Family Singers and what is their importance?

Her "Baroness" title confuses. It is never explained how a person of nobility has the duties of head servant. In many regards, she takes advantage of her position, in that she has Maria take care of tasks such as getting all of the children to school so she can get her morning rest. One wonders if Maria relays this with a tone of sarcasm, or if she is really so willing and humble as not to mind. One also wonders if the rules, which the Baroness attributes to the captain, are not really her rules?