Love the Villain by Rachel Primrose

Jackie’s number one priority is her twin brother. Protecting Ace, keeping him happy and healthy, is what matters most in the world. No one else understands him. Not their workaholic father, their unstable mother, or Ace’s friends. So Ace is Jack’s focus. Does it matter that the whole school thinks she’s a bully if Ace is taken care of?
The only other person who Jack trusts with her twin is Archer Barnes. The nerd is sensitive enough to understand Ace, but not sensitive enough that Jack can hurt him. Archer is there when Jack can’t be, which isn’t too often.
But the years of protecting her brother and putting her life on hold have caught up with Jack. Her dad doesn’t want to put up with her antics and Ace wants room to breathe. When a new kid comes to town, the exact copy of a fictional bad boy, Jack’s priorities might take a turn for the worse. Unless a nerdy hero comes to her rescue…