Is it ok to talk to a girl I really like on facebook everyday?

[Johnny]

I really like this girl and she is really nice and we see each other about once a week at school but we don't really know each other that well. We get along well though. Would girls get annoyed if a boy kept talking to them everyday on facebook? And sometimes I run out of things to say, what is a good way to talk? And I can't ask her for her number or to go out yet I'm not at that stage yet, and will she get mad? Thanks in advance!