The Radiomir makes for a nice piece. I'm not a fan of plated cases but if she fancies the rose gold, do it. I'd personally do a white dial 44mm Luminor model, with pink indices/lume and a nice gen gator strap in a shade of pink or light gray. It makes for a sporty, yet playful watch. The unique, bold colors help ad a whimsical aspect that works well with small wrists...
My wife is trying to steal my fiddy! It look huge on her wrist, but she likes the look.
The 42mm Rad is much loved by my better half - it is apparently very comfortable on a "lady wrist" :lol:
Although, for Christmas, you cannot go wrong with buying the good lady a new vacuum cleaner or steam iron. Both romantic and practical hahaha