she'll find it creepy. the fact that you included a 'you're not ready' option in the poll reflects this.
that being said, you need to have some socially viable way of inserting yourself into a non-church activity with her to get some exposure. you really have said nothing about what this girl's experience or perception of you is.
this - "I figured I'd just call her instead, but when I thought about it I remembered that she's never told me her phone number." - seems like you're lying to yourself. you honestly brainfarted that hard? you have a crush on this girl and it somehow eluded you for a moment that she hasn't given you her number? wouldn't you have had some kind of memorable mental celebration when/if she would have given it to you?
you need to be honest about things if you want advice that is going to work.