book the hero loves heroine but waits until she grow up

[Barbara]

The first book in the Mary Russell series , The Beekeepers Apprentice, has a 15 year old girl becoming the apprentice of a fifty something Sherlock Holmes. In the course of the series, they get married.
I am not in the majority on this book, I didn't like it at all, and Holmes was always a gentleman but the age difference creeped me out a little.

[Ann]

Honest Illusions by Nora Roberts

[MJ]

Wakefield series

https://www.goodreads.com/book/show/1...