Us introverts will often be wide open with family but try to maintain a minimal amount of very high quality friends. Sounds like the only thing she has to worry about is other people worrying about her and not issues that she owns herself.
Introverts are often keen observers of people and can be very socially skilled when it is worth the effort. And sometimes they know exactly what to do to make sure they aren't burdened by low quality acquaintances who'll eat up their independence and energy to unsatisfying effect.
