I've been going back and forth between three and four stars for the rating, but ultimately, I think I've given four stars to books I've enjoyed less, so... rounding it up to four it is.
I'm generally not a romance reader, but I'll make the odd exception, especially when the central romance has anything to do with age gaps or professor/student things, so this one fit quite nicely. Also, while it's definitely a romance-focused book, it did have a pretty decent/interesting time-travel plot in addition, so that helped.
Overall, I'd consider it equal to some of the better fanfic I've read - generally decently written, too, although it could have used another round of polishing (and someone with some knowledge of how certain famous names are spelled, not just how they sound; Dr Jeckle and Mr Hyde
, Kubla Kahn
were both grating and not something I would have expected to find in a book otherwise reasonably well written, if a little random with its comma placement now and then).