On the topic of her large breasts!
I have analyzed this for many years and been with and witnessed naturally large breasted girls as they get older almost always gain weight and the weight most of the (like 95%) of the time surfaces in their bellies.
So you are in great luck!
As far as her into weight gain and loving it......Probably not quite as much as you but you never know.
Most of the time it is the women just relax in a bit and start to get fatter and it is easier than watching what they have been accustom to eating and changing that diet.
Possibly ease into it by telling her how great she look's and if she replies something like...."really I have gotten so Fat" say, "I think you look hotter than ever I wouldn't mind if your cute little belly got even bigger".
8 years
