Murder at first sight

This story is about a 17 yo named Olivia. Her friends and mother call her Olive. She is an spy for the government. You could also call her an assassin since most of her jobs involve killing. She just got back from her last job. She had to kill the mafia boss. She succeeded. Her new job is practically stalking his son. She is investigating whether he is going to continue the mafia businesses. She is undercover as a student at the school he goes to. Her undercover name is Lindsay. She is supposed to represent a rich and popular girl. Her job being Lindsay is getting him to fall in love with her. At least so her trusts her enough.