I wear dresses nearly every day. I wear dresses when half the teachers at my school are wearing jeans or shorts. I wear skirts to my RPG nights when everyone else is in shorts and jeans. Why? Because my dresses and skirts are as comfortable as jammies, I like how I look in them, and because I wanna. No one has ever given me grief over it. It's been remarked on, but in an entirely neutral way. And yes, wearing a particularly pretty/flattering dress on a given day (first day of classes, etc) gives me some extra confidence, and that's true even if I am dressed up more than anyone in the room. Because it's me, and I like it.

LW: dress how you want to dress. If it makes you feel like you fit in more, wear casual dresses with flats, and dress them up after work with jewelry and other accessories, but mostly, dress how you want to dress. Those men in t-shirts and shorts are unlikely to care.