Is my drinking unhealthy?

18 y/o female, I strictly drink once a month (every 4 weeks). Rest of the month entirely sober. But on the one day when I do, I drink like 4-6 shots. I know that any alcohol consumption increases risks of cancer & other health issues. If I drink like this for the next few years, how bad am I screwing up my health? By some standards, my drinking is less than the limit (7 drinks/week for women), but because it’s all in one night, does that make a difference? Thanks!