Answer:
I am not sure about the context of the oldest daughter of this paragraph, but "repress" is a word that often describes the action of not allowing something, especially negative or "unruly" emotions, to be expressed. Forms of repression are usually by force. Perhaps the oldest daughter being repressed means that she was forcibly taught to act more subdued and "ladylike," which translates to repressing any negative demeanors.
Hope this helps!