Probably more of a 3.5 than a 4. Interesting read. Never really read a novel about a conversion story before. (If you know of any that you enjoyed, feel free to post titles under my review) I found it easy to read. It's kind of about a story of divine providence working in an ordinary person's life with unexpected fruit, which is the essence of every conversion story. I liked it enough to want to read volume 2. You're not reading Cardinal Newman here. It relies on cultural stereotypes, not in a bad way, but just in kind of a dumb way.
Other novels I've read about life inside the convent were In this House of Brede by Rumor Godden, which I loved, and the Nun's Story, which I didn't really love because it was basically about a nun losing her faith. Both are novels.