The terrorist attacks of September 11? Old news. Second anniversary of Hurricane Ike? Who cares. For Twihards, the only anniversary that matters this week is the birthday of Bella Swan, the fictional heroine of the Twlight saga.

Yes, Bella, the average girl-next-door who is transformed by the love of a sparkly vampire and a shirtless werewolf, is either 22 or 23 today, depending on who you ask.

(We're not quite sure where they are getting these numbers, since Twilight doesn't seen to specify a year for the events to unfold, so we prefer to think that Bella turns 19 or so every year, the same way Lisa Simpson is always 8.)

Summit Entertainment, the studio behind the Twilight franchise, is encouraging fans to celebrate Bella by seeing the re-released Eclipse again in theaters. Plenty already have since Friday — Eclipse earned $745,000 over the weekend, pushing it to the brink of a $300 million domestic total.

Of course, that's the beauty of becoming a vampire — being immortal means never having to be embarrassed about your age.