This is the best way to flirt with her and find out two things.
Don't doubt yourself too heavily while speaking with her, or she will become uncertain as well.
More so, sending a flirty text to remind her of this can spark some excitement and breathe new life into the conversation.
Don't take the conversation too deep too fast.
Much of the attraction lies in compatibility, and if conversation veers quickly into silence or a discussion that she is clearly uninterested in, then things will sour.
Humor goes a long way in igniting conversations and she will definitely appreciate it.
It is also the most common and effective first step in letting someone know that you like them in a way that is, well, just a little bit more than a friend.