I'm a firm believer that you don't need to change your style too much in order to make it bike friendly. A lot of people are afraid that they'll have to sacrifice their style in order to ride regularly, or make biking their main mode of transportation. In some cases this can be true. If you have a big commute you'll have to factor in getting hot and sweaty, and if you ride all year round and when it's raining that's another consideration, since you don't want to be soaking wet when you arrive at your destination. But for more low-key, around-town riding, you shouldn't have to change your style too much. If you like wearing skirts and dresses, don't worry! There are ways to make your outfits bike-friendly so you can keep wearing the dresses you love wearing.
If it's not too hot out, consider wearing opaque tights. I like wearing tights when I ride because in my mind I'm essentially wearing pants or leggings. If my skirt flies up a bit, it's not like I'll be flashing anyone because you're just getting a glimpse of more tights.
Avoid wearing tight skirts, like bodycon skirts. Sometimes you can make it work, but it's way harder to pedal when your skirt is binding your legs together. Longer, knee-length skirts that aren't very tight are much easier to pedal in, because the fabric allows a lot of freedom to move.