Angela's Ashes: Book vs. Movie

Angela's Ashes, by Frank McCourt, is a memoir about the life of a poor Irish family, and the various challenges they face.
The adaption released in 2000 is pretty accurate to the novel, compared to many other examples. The dialogue often uses direct quotes from the book, which is extremely satisfying after reading the same scene.
For the most part, the cast are okay, but it's not too accurate. I, personally, didn't imagine young Frank's face to be so filled out. The children are described as skin and bones, and the first actor doesn't match that description. Also, his hair is described as always being very messy-- which I found untrue in the movie.
Another thing about the story that's changed, age wise, is the overly rapid progression of Frank's age. At the point where he is supposed to be about thirteen, the actor chosen for the role must be, at the youngest, sixteen.