Girls: Is it bad to go without wearing a bra?

My won't get saggy will they? I've only gone 4 days but I'm a little worried. I've found bras to be so uncomfortable, I don't wear them to bed, I'm not wearing them in public anymore, I just wear a tank top under a shirt so that my s won't look weird and pointed, they still look round. I mean, I wore one to school but took it off when I got home. They're naturally perky now but I worry about them sometimes.