This is not to say, of course, that it's not an interesting read or a good book, just that some things I didn't notice then I recognize now. For example, there's a definite theology to the book that I missed entirely. The references to God are minimal, but full of impact when they occur. Without doing a careful study, I cannot say precisely what L'Engle's theology is, but I'm not entirely sure that I like it.
Another thing that displeased was the ending. The resolution of the story comes suddenly and was, at least for me, pretty unsatisfying. I do wonder whether that resolution had some effect on J.K. Rowling, because it is in some ways reminiscent of the end of Harry Potter and the Sorcerer's Stone. Another comparison I was able to make was that the science fiction bits remind me rather of the first book in C.S. Lewis' space trilogy.
What I loved about this book, and still do, was the understanding that intelligence comes in many forms, and that people are not always whom you expect them to be. Meg and Charles Wallace are both considered slow because they do not live the way 'normal' smart people do. Calvin seems normal, but is actually a huge nerd, who, unfortunately, I do not love quite so much now as I did as a child. He was definitely one of my first loves. A Wrinkle in Time urges the reader to think of the world in a new way, and that is fantastic.
Plus, it has dystopian elements. Hurrah! (Should I be cheering for that?) Anyway, the dark thing that is surrounding planets and instilling negative feelings is working on Earth. It's good to know that much of the trouble humans have is actually not our fault, right? Dystopia via giant, evil alien attacker. Sweet. You could maybe also include the planet Camazotz, which is another kind of dystopian society, although one that was in good functioning order.