Could we really have experienced something paranormal?

I was sleeping in my little sisters room two summers ago while she was away in Illinois with our grandma. As I was laying on her bed staring at the alarm clock it just turned 4:02 am and then I looked at the foot the bed and there was a little girl with short black hair the looked a lot like my little sister that walked from one side of the bed to the other straight into the wall. I was just stunned for a second then I pulled the covers over my head and lied there in shock trying to make sense of what happened. It wasn't because I was tired and was seeing things, I am a night owl and was wide awake. I didn't sleep a wink that night. Then about a week or two after while my little sister was still gone my dog and I were sleeping in her room again (I slept down there because the basement is cooler during summer). I was sitting there looking through my phone when my dog woke up out of sleep and starting growling. I kept trying to get him to quick. He growled for about a minute straight. Then all of a sudden the bedroom door flew open so hard it bounced of the wall and made me and my dog jump. I just sat there again stared at the door way. My dog started growling again and crept off the bed and scoped the situation. He walked around the basement for a few minutes growling with the hair on his back standing up and then came and snuggled up to me lied awake with me. Having my dog there comfort me... I wasn't as scared the second time either. A couple days went by and I told my big sister what was going on. She then told me that her and her boyfriend were sitting in her room upstairs with the door opened and a she saw a little girl walk past her door. She wasn't going to say anything because I am terrified a paranormal things. But once my little sister got back we haven't noticed anything since. I'm not sure what to make of it? Why would it magically start and stop?