Ehhhh... I'm not into the idea of posting on her ウォール wishing her a "happy birthday". I don't know her. It would just seem awkward to me. Bring her here to see this 質問 so that she can see me wish her a happy birthday here.
Yeah because having a total stranger who she haven't met before her entire life greet her a happy birthday will cheer her up and not mark あなた as a creepy stalker.