False Star by Jessica Ruddick

As an engineering major at Virginia Valley University, Becca Zizzo is used to being the only girl in the room. Until now, it didn’t bother her to be just one of the guys. But she’s been in love with her older brother’s best friend half her life, and she’s sick of spending time in his friend zone. She’s studied his playbook, and she’s ready to go big or go home.
Tight end Carson Fleck has spent most of his life not living up to his family’s expectations, so who can blame him for not taking life seriously. He’s only ever been good at two things–scoring in football and with the ladies. Okay, and maybe a third thing–scaring off the losers who want to date his best pal’s little sister. But when he realizes his feelings for Becca go beyond the need to protect her, he has to figure out how to become the man she deserves.