I read this book in middle school but never finished it. It was about a girl who was playing a video game or got sucked in and she was a female knight but she kept dying but she apparently got cursed by the evil mage in the game so that if she died a 3rd time she would actually die. The cover of the book had a girl standing in armor if I remember correctly but her face wasn't in the picture. She was holding a sword by the hilt with the blade pointed downward. It was a really great book and I'd really love to finish it. I think the word "heir" was involved in the title somehow. Thank you for any help anyone can give.