I had about 500 ml of Rum and I feel not as drunk as I hoped

I’ve been drinking between 5pm and 10pm. I weigh 97 kg. I had all this Rum hoping I would get very drunk but I feel more or less the same as I would if I had about 6 cans of 3.5% beers. I can barely tell that I am drunk. I would call it more of a tipsy feeling. I am still very much in control of how I talk, react or act.