Is there a specific question you're trying to ask?
The fact that you call them Demons worries me... Demons are bad entities that you don't want to EVER deal with. I've been followed home by one of them and I will never forget what I experienced that night.
You say that you're fifteen and that you can see spirits, there are a lot of people that can and this ability usually happens to kids at a young age. I had my first paranormal experience when I was 8 and ever since then, I can sense when something is in the room with me.. I can't see them like my sister can, I can just feel them. It feels like when someone just walks into a room you turn around expecting to see someone but no one is there.
As for you being able to see them, yes it can be a scary and if you don't want to experience that just ignore it, I don't know how you do that though because you say you can see them just like a real person. That's the only thing I can think of, if that doesn't work you can try posting a question about how to do it, I'm sure others will comment with the same ability and how they can control it.
I hope this helps at least a tiny bit!