Elena turns into a vampire in the 3rd book, The Fury. Actually in the very end of The Struggle but it is explained better in The Fury. Initially she thinks she is in 사랑 with Damon because he is her creator and as she is still confused, having turned into a vampire and all, she wishes no harm come to her creator. But later when her mind is clear again and she remembers who she is and what happened she remembers Stefan and her 사랑 for him although after what happened a part of her loves Damon and she's having difficulty to choose.
Elena gets turned into a Vampire and she wakes up and she's all confused and can't remember she is in 사랑 with Stefan, she only knows his name and that he's Damon's brother and like I said, she's confused and she thinks she is in 사랑 with Damon so she goes off with him and he gives her her first Diary and she sleeps then she wakes back up and reads her Diary and remembers everything again. She is not in 사랑 with Damon.
Yes Elena get turned when she drowns in the creek, when she awakes she is confused and thinks she is in 사랑 with Damon, but thank goodness it does not last, although she has a new appreciation for him but her 심장 is with Stephan. I have not read enough yet to know who turned her BUT it is not Damon 또는 Stephan. If 당신 are watching the series on TV things are so far quite different :o)