I haven't read it in probably 15 years, but I loved it so so so much as a teenager and young adult. L'Engle wrote a lot of nonfiction, actually, and it always meant more to me than her fiction. She was a very liberal Episcopalian and most of her nonfiction was explicitly Christian while still being very...open? Expansive? I can't say for sure, but I feel like if I went back and reread it, there would be things that no longer resonate with me, but other things would still be true, and I wouldn't be annoyed at her particular brand of Christianity. Honestly, I should reread it just to see how it works for me now!