Wear what you want and be safe.

If you wore a skirt, I hope you are not riding a bike with regular top tube. And better make sure your skirt does not get sucked into the wheels.

I've had desires in the past to ride a crummy looking bike, with streamers on the handle bar ends, a pink basket on the drop handle bars and few other acrutments to say I'm a Wilma then blow the snobby posers who think they are uber cool cause they wore the "same" kit as the pro teams.

I wear gloves cause my hands feel better during and after the ride.
I wear a jersey cause the back pockets are in the "right" place to carry things.
I wear a cycling pants cause my tush feels better during and after the ride.
I wear a cycling shoes with cleats because its easier to ride.
When its hot outside, I wear a skull cap and roll up the edges so as to wick away the sweat and keep it out of my eyes.
I wear sunglasses, cause I don't like wind and debris blowing into my eyes. Though I admit, I like cool looking sunglasses.
Lastly, I wear a helmet. AND IF YOU NEED A REASON THEN YOU SHOULD BE WALKING.

Fashionistas are enslaved to the Madison Ave. marketing hype!