Dreaming about someone who ped away?

Do you believe that the dead visit us in our dreams? Last night I had a dream that I saw my grandmother. She died 6 years ago when I was only ten years old. We were very close, she was like a second mom to me. In the dream, she came up to me and gave me a hug. I was crying and told her I loved her and I missed her so much. She told me she loved me too. Then she went on to tell me to please be stop being sad all the time because I deserve to be happy. She also said she's okay and I need to stop worrying about her. I dream about her every few months, but she never talks in the dreams. I want to believe she was visiting me, but I don't know. Maybe it's just my subconscious. What do you guys think about this?