I tried to answer this the other day, but the 'net had other ideas. The 'Da Vinci Code' was longish - but she has evidently never read a full Dickens novel.
I would like to point out that these were published in weekly instalments and the lowest maidservant would buy them to be read aloud to fellow servants.
Later, we did. of course, read them as full novels. After I borrowed a class set of 'Great Expectations' from Bradford Schools' lending service; I was offered the option of keeping them as we were the only school in Bradford which had borrowed them in years. YET I had no problem in interesting my pupils in the story. Q.E.D.. Expectation is all. Children learn what we face them with.