Falling in Love by Ava Reese

Bailey climbed a mountain for the challenge and came down with a crush.
Whip-smart, stubborn Bailey can do anything she sets her mind to — including climbing a mountain by herself. What could go wrong? She finds out what, when she falls off the mountain and into the arms of a handsome hiker named Shawn.
Back in Texas, she expects the rest of her life to go as planned. But when Shawn shows up to teach her graduate school class, that illusion shatters. Their university forbids student-teacher relationships, so Bailey puts him out of her mind.
She decides to focus on… how his eyes sparkle when he looks at her. And the jokes that only they understand. And the way his muscles rippled that time he carried her over the mountain.
For someone who likes to follow the rules, Bailey may be in a lot of trouble.