My Friend Is Scared Of Her Ability

I have a best friend that I have known since the 4th grade (I'm going to be a freshman in high school this school year). We share all our secrets with each other and something that she hasn't told anyone else is that she has the ability to see and talk to ghosts. But she does not like having this power. She just wants to be normal and not have any gifts. Some of her family has this ability too and they all embrace it, but she hates it. She says bad things come to her and stuff but she's a comical person, so she makes it funny, which makes me think maybe somewhere deep inside she doesn't mind having this power. She is terrified of anything scary so when she sees these ghosts and things she freezes up. One time we were taking a walk together and she just stopped in the middle of the sidewalk, I snapped her out of it but she kept looking back. Sometimes it's the hardest thing for her to deal with. I keep telling her maybe if she learns to control her power and understands it and its limits maybe she could turn it off, but she is just so against it. She can't even talk about it without hesitating. She's the only person I know that has powers so we can relate about things. My questions are how can I get her out of her shell and how I can make her use her ability or just talk about it more. I want to test her ability and see what her limits are and help her control it so how could I do that. What are some exercises or techniques that she could do to maybe stop it from happening or make it happen when she wants. Does anyone have friends like this or are you like this? How do a mediums powers work and what are your limitations with it? Thanks:)