Yep that is the obvious solution mrz. But she's stubborn and she's reading silently to herself, so it's hard to police! To rephrase: keen and able readers are likely to push themselves beyond their comfort zone, which means they are likely to be doing what lots of teachers on this thread say is a cardinal sin, namely guessing from context and skipping hard words because they are wanting to get to the next bit quickly! To me, I guess, this seems acceptable since they are gaining other things from reading difficult books, namely reading enjoyment and speed/fluency. Otherwise, the answer seems to be that you push them back to stuff they can read easily but will bore them. But maybe I just leave that problem to her teachers, and let her read whatever takes her fancy at home!