Now that The Vampire Diaries' Elena Gilbert is turning into a vampire, there's one question on everyone's mind: How long will it be before she has some hot, vampy sex? The short answer: You may have to wait a while. "I'm not going to say she's not having loads of vampire sex off camera that we're not showing, but we have not yet shot a complete sexual act this season between Elena and anybody," executive producer Julie Plec tells TVGuide.com. Exclusive: Find out the name of The Vampire…