How much is too much?

Hi! I am not a big drinker at all, all alcohol I’ve tried so far (which is only red and rose wine and cava) have not tasted very good to me. I also have emetophobia, which is an extreme and irrational fear of myself or others vomiting. This has led me to be very scared of getting drunk, but because of not drinking a lot, I think I would get drunk very easily. I turn 18 next year which means I can legally drink at bars and clubs. So now my question is, how much can I drink without getting too drunk? I’m 166cm/5’5 and 56kg/123lbs, and like I said, I have barely drank alcohol before. Some drinks that I want to try are cosmopolitan, martini and mojito. Can I have one whole drink of those without noticing it too much?

I’m sorry if this seems like a ridiculous post, I just have a lot of anxiety but still want to fit in.