Maybe she lied about it, because she thought you were just a one night stand or one afternoon stand what ever, and now she's stuck with it but really doesn't like sucking dick. I had a girlfriend who did that,I just sat, if you don't do it I'll go find someone who will... And she started sucking like a lil' baby on a niple :D.
If that doesn't work, don't eat her pussy either haha.
Cheers mate.