Most girls wouldn't know that much. There's a lot of online articles about this to teach girls how to give a better blowjob and tell what usually works. Although, most guys can't orgasm with oral alone - usually half of it is masturbating by her or you.
I don't think you should be so hard on her saying "are all girls this clueless"? A lot of girls really don't know how to give a good blowjob - they have a pussy and not a dick, so it's different and they have to learn from a few times
You should talk this over with her or a future girlfriend and see if she either wants to have oral sex and if she knows how to do it. You're both new to it...so learn from each other! =]