How to dress for church in winter?

Hi all. I'm having a bit of a dilemma. My boyfriend is going to Kuwait next month and before he goes he is taking leave this week so we will be visiting his family. He's from Ohio and I'm from Texas so I haven't been up north much less experience the weather. I'm afraid I may not be appropriately dressed for church and the weather. When I was in high school my church was pretty casual and people mostly wore nice shirts or even just jeans and t-shirts. I was thinking about wearing a nice dress and maybe pantyhose but I'm not sure what else I would wear. I don't know if i should wear boots or dressy shoes. What could I wear to stay warm but still look nice? If it's any help, I'm 19 years old so I want look like an adult but not too old. Thanks!