my mom judging that I drink

I am a 21f and Its now Saturday and i bought myself a six pack of apple cider just to drink one and store the rest. btw the legal drinking age here is 18 so its not like i’m new to drinking. I never over drink i havent drunk more then 5 drinks in one day in my life. I just want a drink but when i got home with the sixpack my mum judged me so hard. i dont understand? i have a drink when im on holiday, at a party, when i travel. my dad sometimes has a beer on the weekend. its not like there has been alcohol abuse in our family. i dont understand why she judges me. i just wanna enjoy one drink which has less alcohol then a beer. I feel bad but i just wanna enjoy a drink on the weekend