Because she already has this "the holidays have always been a blue/down time for me" preconception, and if i drop all of this on her right now i am being "more of the same hoosjim" that she associates with crappy holidays.
On the other hand, it could give her a taste of just how wonderful Christmas would be with the OM. They could drink beer and tow cars on Christmas Eve and binge watch Ice Road Truckers on Christmas Day.
