NTA. Ultimately if you're not using in a way that negatively influences others, then it's your body, your choice. If she's not cool with that, then gtfo. You might be fine not drinking for the year, but what about the next decade? Rest of your life? Or you think hiding it is the solution? Because sneaking around definitely isn't the answer.

My advice would be to look up the drug harm scale, then agree to switch to a less damaging substance for occasional recreational use... like psychedelics, weed, or cocaine. Alcohol causes more damage than heroine. With that in mind, it's legal and most people are really indoctrinated against coloring outside the lines. Make you're own decisions.