Ghost Great Grandmother? Did we really see her?

My great grandmother died last February and me and my mom had both seen it.My mom felt her presence and seen her.(but she was white you know what i mean) I saw her in color I told my mom I said she had brown hair and was wearing a red dress I asked my mom. she said she always wore dresses. Kelsey my great-grandmas daughter.Said her favorite color was red and Kelsey said she has seen her too. Is this possible?