First time I’ve ever had alcohol, yet I don’t feel any changes.

I’m doing a test on myself to see if I would feel comfortable being drunk in front if other people and have had one shot of gin with an alcohol content of ~40% as well as two half shots of ~20% with 45min spaces in between. I’ve been using a BAC calculator on the internet which tells me that currently I should have a BAC of 0.21. I’m fine with this being the result of my diy test but I also though that given my small height(170cm), weight(60kg)and the fact that I’ve never had alcohol before, that I would have been falling over every one of my steps by now, is anyone able to expla to me what might be going on?