Does a girl like you if you had class with her last year and you go to the same church and she smiles at you every time she sees you but you never get the chance to talk?
There's a good chance that she does like you, but you won't know unless you talk to her. What's the worst that will happen? I suppose that would be that you open your mouth, say something really stupid about the color of her dress or maybe ask what brand of hair coloring she uses, she slaps you and you never speak to her again... well... you aren't talking to her now.
Be nice, talk to her like a gentleman, see what she has to say. LISTEN!!! Find out what SHE thinks is important. Chicks dig it when guys listen. ;)