and waiting around after we have attended a church event to walk outside with me to the parking lot.
OK, in my book that is a clear signal that she's interested. She's seeking you out, waiting for moments she can spend time with you.
From her background mentioned, a group setting would be the first step. She wants to see how you fit in with her friends, etc, and is not ready just yet for a one on one outing.
If you are interested, either say yes the next time she asks no matter what (after three no's I think she'd be feeling pretty low), or tell her you would really like to get together and feel bad about not being able to say yes to her invitations and you arrange a similar group event together with a mutually agreeable date/time/place.