Is it ok to start wearing maternity shirts at 21 weeks?

Le

I got by until now by wearing large flowy shirts but I think I finally have a cute bump and I want to wear a maternity shirt to work tomorrow. Am I pushing it for 21 weeks or is it ok to start showing off my bump? #ftm #selfconscious

Edit. I know it’s ok to do whatever I feel like but is it along the regular timeline for pregnancy progression?