Good idea for a story, or not?

It is about two main people, 12 year old Antanasia Svensson and her 5 year sister Mimi, they are from Sweeden. They were twins, non-dentical, but when they were both 5, Mimi got bitten by a vampire, the same one who killed their parents while they watched, for the past 7 years Antanasia has been looking after her sister, stealing bloodbags for her if neccessary. They made their way to a small town in North Carolina called Parksville. Soon after, Antanasia reveals to her sister that she is ill, and that she will die. One day, Antanasia is kidnapped by a vampire, the 12(Actually a lot older but appears this way) year old son of the vampire who killed her parents. He was fallen in love with her and wants to make her his, she refuses, but he is so annoyed he doesn't notice that she is ill and locks her in a room till she comes to her senses. Meanwhile Mimi is out looking for Antanasia, without any luck. Mimi finds out from a vampire who saw her sister get kidnapped that the son is evil and a bite from him will make you a vampire, but very painflly, and they seem rabid until it is over, and that he knews where they are. Mimi goes to the place and finds Antanasia sitting in the corner, she helps her sister up but then sees that Antanasia was bitten, she backs off and watches as she is about to kill her. The son stops Antanasia, saying that it isn't time yet. Antanasia howls in pain but the son strokes her head, saying that it's allright. Mimi has a flashback to when they were 5 and their parents were killed. Antanasia goes through the slow painful transformation into a vampire, but in her head she is denying everything that has happened, at the end she collapses, then Mimi comes in, and Antanasia looks up, with fangs and glowing red eyes