Girls are pretty sensible about weight and gaining, both on themselves and others, expecially their partner and most of all if he had a six pack to begin with.
Some years ago I realized my gf was particularly happy with my body. I had always been lean and muscular so I was pretty confident so I paid little attention, even if I had abandoned my track and field training a few months before. More months passed and she was looking more and more happy. At the end she confessed she was enjoying looking at my six pack vanishing and at my gut growing. I hadn't even realized I had been gaining, but for her it was clear since the first pounds. She confessed she was loving my softened belly only after my six pack was totally gone. I had already put on 20 pounds by then. She said nothing before because she was afraid I could get self-conscious and diet. Moreover she said she was happy I was softer because she considered I was more "hers", as she was adding some meat with her cooking.
So, chances are that she has noticed your six pack is gone, and she is liking your fatter belly, but she doesn't know if you are aware you have gained, and is afraid afraid you could get back. Try to complain about your trouser getting tight

Oh, I know the feeling. I was camping at a lake with my girlfriend when her parents reached us. They had not seen her daughter for a whole year, since we moved away, and she had been putting some meat on her bones in the meanwhile. It was just a few pounds at the beginning, bringing her at a normal weight instead of her usual thinness, so she paid no attention. But as months passed more pounds piled, and her curves blossomed. She wasn't complaining about her curves, but at a certain point started to remark with concern on her softening waist. Slowly she got that shapely, well-fed look I adore. Even a tad too much "well-fed" at the end of that year, as she remarked trying on her old bikini. But there was no time for dieting as we were packing and leaving for our vacation in a week. And there her parents caught us. Her mother was clearly surprised by how much softer she was looking. Decidedly her curves had developed and softened to the point she was spilling out of her bikini. Her bottom's strings were digging her sides, while her belly was bulging and looking jiggly. Her softened thighs and bum wasn't helping dissimulating her gain as well. Our small camp chair was pretty much hidden below their new spreading softness.
She wasn't fat, just a bit overweight in a not forgiving outfit. And that was a pleasure for me to see. But her mother sounded way more alarmed than pleased. "OMG girl! You plumped up so much, you are.. you are OVERFLOWING everywhere!" My gf was totally embarrassed as her mother kept asking how much had she gained, and just blurted out "not that much", but failed to convince her parents.
That evening we dined all together. Her mother was struggling to refrain from making any further comment, but after looking at her daughter enjoying her meal from the appetizer to the dessert, through a rich main course, and cleaning greedily all of her plates, couldn't help herself any longer, and sentenced "no surprise you have filled out so much girl, if that is the way you are eating every day at home, you won't fit in your clothes by the very next year."

OMG! And you still have to go through all of the X-mas feasts! i think the New Year will look at a new girl.. nomoreskinnyATALL

Wow, ambitious target for you! But I'm confident that your resort vacation can easily contribute with a good dozen of pounds, and multiple Christmes feasts should do the rest! Don't forget to ask Santa Claus for bigger clothes under the tree!

Have you just enjoyed that or helped somehow, like cooking more, more fat food, ecc?

Which are your motvations?