You can post links to the kind of clothes I should buy. And am about average size and height.
Most Helpful Girl
It depends on the church, at the one I used to go to skinny jeans and a cute top would've been fine. I'd say ask someone or go in a summer dress. As long as the dress isn't too short you should be okay. Maybe wear a light cardigan if it has thin straps.
Depends on your style I guess, but here's a few:
link (one on the left)