She wants you to qualify her. Get on a date with her first (which I am pretty sure you havent done yet). Qualifying is the process of telling a girl why you like her by telling her what makes you attracted to her THAT IS NOT HER LOOKS!
If you do this too easily and soon she will think you are easy and lose attraction for you, but if you never do it at all she will think you ain't attracted to her! Whatever you have been doing up to now to get a quote like that out of her keep doing it. Seems to me you are doing a good job. Keep playing it c&f.
btw yes it is a test and she is testing to see if you are a man (hard to get) or just another easy chump that is ready to confess his puppy love for her. What do you think will work best? 2 replies you could use
hero: I think you are nice/beautiful/whatever other compliment you can think off to reply to her question
OR
hero: You are going way too fast for me. BTW I gotta go meet up with some friends i'll call you back!
hint: it ain't #1
I mean seriously brother get on a date with this girl first, make her earn your respect.