Ha ha ha.
That's weird, Sades, we have the same story around here now.
At least, when I was in third grade.
I remember though there was even more attached to it, yes, the mirror, the candle, but you said Bloody Mary three times, turned around once said Bloody Mary another three times and then clapped your hands three times and something or someone was meant to stab you in the back -- out of nowhere. Of course, not ever ever clapped three times. We all used to think the kids who clapped twice were brave....
Another Urban Legend [this one had me freaking for weeks afterwards] was that a man and woman were driving along a country road when they ran out of gas [how convinient]. The guy said he would walk to town and get some petrol, and he went and they locked all the doors so she would be safe and she slept all night in the dark with no problem and in the morning she woke up and he still wasn't back. She turned on the cars radio and they were talking about a serial killer on the loose, a guy who would murder people with his incredibly long fingernails [sigh]. And that night he still wasn't back and she was getting worried. Then a police car drove up behind her, but she only noticed it when there was no one in it, and she couldn't see the cop. Then there was a knock on her window, and thinking it was the cop she got out....
...and on the roof of the car was this man with long fingernails with her husbands head impaled upon them, the killer slowly chuckling and chewing the guys ear.
I was scared shitless of everything and everyone for weeks on end. In the end my best friend had to talk me into believing that the story couldn't be true because a serial killer doesn't kill people.
It kills cereal. Like breakfast.
My secret shame.