"If I let go of my fear, what is there to keep the power I feel in line?" She understands that the Force is strong with her. She's heard it several times before arriving here, and can feel that it's strong within her even if she has no idea what to do with the power.

"I should be afraid, of what I can do to others." Her voice trembles with emotion. Fear is healthy for her right now. Fear is what keeps her from giving in to the power she's discovered she has and being just like Kylo Ren.

Or perhaps Obi-Wan is right and fear is what will make her exactly like him.