A person who has influenced my life is my mom.
I can tell her everything.
I can tell her why I felt sad, what happened at school. what made me happy. = I can tell her why I feel sad, what happens at school, and what makes me happy.
My mom always hears them. = My mom always listens to me.
She focuses on my talking. = She focuses on what I say.
So. she influenced my life the most. = So, she has influenced my life the most.