I asked this girl out on facebook she sayed no and read the descriiption i NEED HELP!?

I asked this girl out on facebook she said no. I have asked the question on here and answerd helpful that i ask her out after school. I was just on facebook and i have just noticed she has unfriended me and shes in my class and she even has unpopular kids on her friend list. Is it worth asking her out in like a month? the main question is (is it worth trying to ask her out after school)?